[Delmain Tweaks - Vanilla Fishing Expanded - Start of stack trace]
Verse.PatchOperationAdd(xpath="/Defs/TraitDef[defName="VCEF_Fisherman"]/degreeDatas/li[label="fisherman"]"): Failed to find a node with the given xpath
Verse.PatchOperationConditional(xpath=/Defs/TraitDef[defName="VCEF_Fisherman"]/degreeDatas/li[label="fisherman"]/statFactors): Error in <nomatch>
[End of stack trace]
The top operation is the one that failed, the ones below it are the parents
Source file: C:\Program Files (x86)\Steam\steamapps\workshop\content\294100\2959696593\1.4\Patches\VE-Fishing.xml

[Delmain Tweaks - Vanilla Fishing Expanded] Patch operation Verse.PatchOperationConditional(/Defs/TraitDef[defName="VCEF_Fisherman"]/degreeDatas/li[label="fisherman"]/statFactors) failed
file: C:\Program Files (x86)\Steam\steamapps\workshop\content\294100\2959696593\1.4\Patches\VE-Fishing.xml

That's what would come up if the Fisherman background doesn't exist. Make sure that you have VE Fishing installed, it's above this mod in the modlist, and that you didn't disable the Fisherman background with CherryPicker or something like that.

VE Fishing is installed and background wasn't disabled and your mod was below that in the modlist. Cheers for the information, I'll poke around and see if I can get it to consistently pop on load with a smaller modlist, if so I'll toss a link to a pastebin.

I'll just chalk it up to a hiccup in the matrix. Nothing was redownloaded, or moved in modlist order, and after some closing the game and relaunching the error was no longer there. Even the player.log was different with:

[DelmainTweaks.VanillaFishingExpanded] Mod Loading Complete!

Sorry about that!

There are a lot of performance mods which can cause temporary things like that. If it's resolved now, no worries!

swapped to justpaste because pastebin is crazy : https://justpaste.it/d4ve9

You say the bug shows up with just VFE Core, VFE, and this mod. Can you share a log with that failure? This log has considerably more mods than that, and is even in a format that I've never seen for a Rimworld mod.

And a HugsLib log would greatly be appreciated because it outputs which mods are using Harmony detours on specific methods, which I need to try to figure out what has happened.

Well, I finally encountered that issue myself. It looks like there was a VE-Fishing update and it broke one of my transpilers. The issue has been resolved with a new version pushed to Steam.