Update:
Discard problematic method
Allow Remove/Smooth/Paint floors under the diagonal walls

@GVLT
In the screenshot I put up 7 hours ago, I had already tested the wall narrowed that way.
Anyway, I once again observed people working in the room above.
https://steamcommunity.com/sharedfiles/filedetails/?id=3352175156
Rex reached Lea via an diagonal path, after which Lea was well taken care by some people
When I first loaded your save after starting the game, I got a bunch of errors, so I'm testing by loading another map once and then loading your save
If you're getting red errors on load as well, that's not a problem you can ignore

Now the problem is not in the trashbins, but every pawn trying to do their jobs in this room
https://drive.google.com/file/d/1-H_1fgVm6oR0fXFc_SrDKletk-oS39Eq/view?usp=sharing
What happens if you try to build the wall like this and then force pawn to do something in the room?
CE errors are produced by stuff that wasn't patched and I removed, pretty much harmless.

@GVLT
In your mod list, I reproduced all the mods (except Some Things Float and MobileDragoon (that is WIP), Because witch made the game unplayable in my environment (probably some compatibility issue)), and observed your colony
Set up storage in the room and set the priority to critical ,and I saw trashbins bring stuff into that storage
https://steamcommunity.com/sharedfiles/filedetails/?id=3351900117
Maybe there is no problem with pathfinding. It could be some other mod settings or ...in my environment I was getting CE related job errors every few seconds. I think you need to check those errors and address them one by one

Hello again. I can build floors under diagonal walls, just can't paint them.
Yes, AI can get into the room while drafted, but now on it's own. No path
https://drive.google.com/file/d/1-DDqXRWlW6XY5CSrU-ZCCaFWsJXSkwFB/view?usp=sharing
Here's the save. Notice the bedroom on the left side with the decals on floor. It's unreachable

@GVLT
Test result
Can you identify in more detail the conditions under which the problem occurs, or share the save data with me again.

@Atomically Wrinkled Brain
OK discard that method once. It was to avoid minor errors, but it seems to cause more serious errors.
You have confirmed that the mod is up to date, right? （steam doesn't always update it） If it still happens, I'll try to find a better way.
BTW, what was the map size? The error looks like it's happening in the corner of the map.

@GVLT
Does this mean that the pawn AI won't try to get through the narrow path, although it can get through it in a drafted state? I'll look into it.
The ability to build floors under walls is included in NANAME Floors , but is not supported for painting. If I add it, I'd like it to be that mod, is that OK ?

Pawns still can't build something until forced in the areas which are behind narrow diagonal hallways, but I can manage it. Can ability to paint floor under diagonal wall be added?

Exception ticking Egan (at (103, 0, 3)): System.IndexOutOfRangeException: Index was outside the bounds of the array.
at PassingBetweenDiagonalWalls.Patch_RegionCostCalculator_PathableNeighborIndices.Postfix (System.Int32 index, Verse.Map ___map, Verse.AI.PathingContext ___pathingContext, System.Collections.Generic.List`1[T] __result) [0x00099] in <58fcb6c25b234941a8d658ae1f95aeb8>:0
at (wrapper dynamic-method) Verse.AI.RegionCostCalculator.Verse.AI.RegionCostCalculator.PathableNeighborIndices_Patch1(Verse.AI.RegionCostCalculator,int)
at Verse.AI.RegionCostCalculator.PreciseRegionLinkDistancesNeighborsGetter (System.Int32 node, Verse.Region region) [0x00017] in <cd7169108ea74757aa50c5b33d275c15>:0
at Verse.AI.RegionCostCalculator+<>c__DisplayClass38_0.<GetPreciseRegionLinkDistances>b__0 (System.Int32 x) [0x00000] in

wonderful mods

@GVLT
https://steamcommunity.com/profiles/76561198322678771/screenshots/
Of course it's passable
The walls contained in the DiagonalWallList.xml in the mod folder should be passable.
To keep your mods up to date, re-subscribe after every update, Steam's automatic updates are not always reliable.
Or whenever you restart Steam, it should be checked

The one on your last screen is accessible via straight line from the left. Try block it
I have no idea actually. Maybe removing and then installing mod back helped something.

@GVLT
Or rather, what happened to the IndexOutOfRangeException error? I haven't found a solution yet.

@GVLT
? where?
https://steamcommunity.com/sharedfiles/filedetails/?id=3348957755
https://steamcommunity.com/sharedfiles/filedetails/?id=3348957837

https://drive.google.com/file/d/1-CdYoCC0T3wuHRcPQQ-t1XA8q8MIeD5t/view?usp=sharing
It seems that problems regarding lag are gone, but there is a slight problem now: pawns are not building things way to which are routed trough diagonal walls. Look for example at screenshot I provided.

It's even the wildlife that is deciding to leave the map. Even enemies fleeing from the other maps like encounters and bandits raids. May it be because entrance to the base is lined up with diagonal walls and deep inside there is a map exit I've excavated? I would not think that Passable Diagonal Walls is the culprit if removing it wont solve the problem, but it did.

＠GVLT
I thought about it quite a bit, but I'm pretty sure I've handled where that error can occur.
And I couldn't reproduce the bug.
You're not using the github version, are you? I hadn't pushed it there yet.
It shouldn't happen with the steam version.
Can you tell me more precisely the circumstances under which it happens. Is it when a pawn is put out to caravan?

Well, the index array error is completely new to me.

@GVLT
The part that was causing the problem was the same as expected, but the last update didn't fix the problem? That's odd

https://drive.google.com/file/d/1-9XUEFjxPDonZlAtxA07uBRxwsHt8kbh/view
Here is the link, though not the one where I spotted Passable Walls in the console, but exception is the same.

@GVLT
hmm that's a little hard to resolve without a log.
I could not confirm the same issue here. I added a check in the suspect area and updated it, but if it's not fixed, give me the log.

Okay, 10th october update introduced System.IndexOutOfRangeException: Index was outside the bounds of the array. for any entity trying to leave the map, sometimes just move trough. Removing the mod fixes the issue.

That's okay for development, hope I'm not annoying

@GVLT
Oh dang it. it slipped my mind
This time I made sure that every problem that has ever occurred would not occur
Sorry to make you report it so many times. Next time you have the same problem, punch me

Last update again introduced pawns trying to build stuff behind diagonal walls and failing.

@Sir Humphrey Appleby
The process of trial and error had reoccurred problems that had been solved before. Thanks for letting me know. It's already solved.

I've had no issues with pathfinding but I just noticed that my diagonal walls are all embrasures. By that I mean I build with regular diagonal walls but the building isn't designated as a room. It's still outdoors. Remove Diagonal Pathing and buildings are indoors again.

I see you're in the middle of something so it probably has to do with the temp fix. Just stopped by to let you know and to thank you again for the mod.

>Tests have shown that this problem goes away after a save/load
Yea, told you so. I will get the new version then.

I've updated it, but it's a symptomatic solution that I don't like, consider it a tmpfix. Anyway, it should avoid the fatal problem.

@GVLT
Wait, I haven't updated it yet lol.
Tests have shown that this problem goes away after a save/load. So I guess you just haven't run into the problem yet. I'm working on it, so you'll have to wait a bit for a complete fix.

Playing for a hour and no bins stuck so far. Great job, thank you!

@GVLT
OK, I was finally able to reproduce the situation with a small list of mods. Apparently the problem was not what I thought it was. I think I will finally be able to fix the problem now. Sorry it took so long

I think you can test it by making pretty long shaft out of diagonal walls, spawn there loads of haulable stuff and see if A LOT of trashbins would be able to carry it or if they stuck. Also, after update amount of stucking for trashbins is much higher than on previous version. Can you share it with me?

@GVLT
Updated.
Maybe it's fixed, but ...... is a little hard to test. If it's not fixed I'll look into it more closely.

Looks like after the update pawns are trying to do stuff that are behind the diagonal walls.

@GVLT
As for the lag, once you clear the logs in game, it seems like you're getting every tick errors in places that have nothing to do with my mod

Hi, pardon me, I've misguided you. I've used installed perfect pathfinding and found situation improving a bit.
Clean pathfinding on the other hand produces pulsating lag spikes for me on this map making the game unplayable

@GVLT
I have a patch that I've applied to Clean Pathfinding but not to Perfect Pathfinding. I was limiting it because it changes the roofing behavior around diagonal walls just a little bit, but I think I should apply this to the base game
I just released an update. But it will need observation for a while
I think it's okay to go back to Perfect Pathfinding now, but let me know if you run into any more problems.

https://drive.google.com/file/d/1-79DQYWpR_ettN3nPEbfFxqH-h7HGA2k/view?usp=sharing
I've installed clean pathfinding today to try to resolve the issue. I must say it helped a bit. Overall the lag spikes are gone for some time on save reload.

@GVLT
I tried replicating the mod list and let colonists and trashbins haul to a room that is only accessible by a narrow diagonal path, but that didn't seem to cause any problems
The situation may be more unique
I'm considering the possibility that dirty avoidance feature of Perfect Pathfinding is related
If you want more support, send me your save file by any way

Thank you. It's rare to see such will to help

@GVLT
Unfortunately I haven't been able to reproduce the situation yet, I'll try to reproduce the mod list. For reference, patching the same locations are VFE Security, VFE Insectoids 2, Perfect Pathfinding, and CE.

Removing the diagonal narrow path works too

So the issue for me persists if between hauler and it's target only possible way is this narrow diagonal path. If I manually move hauler past them they work correctly.

https://drive.google.com/file/d/1GkL9LsTbV9Md8aunBqGdM52XowjCOKSp/view?usp=sharing
Here is the link for the log. Hope that helps

Okay, it seems that hugslib share is not working anymore

I would be happy to. I have a somewhat huge base and an army on 15 trashbins which are hauling bots working on VEF. I also use adaptive storage. MOST of the time trashbots are forced to pathfind trough areas encapsulated with diagonal walls they just paint a straight line to target and continue to stay in place producing errors until drafted and manually moved.
I will try to remove "Pick Up And Haul" in case there is an incompatibility between this mod, Adaptive Framework and your mod and will post log If no avail.

@GVLT
If you are the one who can give me the information I need, such as HugsLib logs, conditions that happen, save files, etc., I'm active in fixing it.

I'm using this mod heavily and I have some immense pathfinding problems around the areas with diagonal passages. Anyone encountered this previously?

@Nin-Sama
I applied the patch applied to Clean Pathfinding to the Pathfinding Framework as well.
If this does not solve the problem, I think I need to get a save file, as this problem is a bit difficult to reproduce.