Thanks for this, I analyzed it, the cause is completely different. Here is the new v4.0 fix:
https://steamcommunity.com/sharedfiles/filedetails/?id=3518290482

Hello. You were asking for a bug report/save file for this issue happening in v4. I am not sure if you will see it in the thread we were in so I will leave a link here as well.

https://forum.paradoxplaza.com/forum/threads/stellaris-phoenix-v4-0-21-bb43-cyberization-still-converting-main-species-into-random-pop.1817036/

yea this is a issue hapenning there mate i wish i cood give out a bug report but i do not know how to give out a bug report so this can be fixed very annoying

will this be updated to 4.0?

If someone has a new bug-report with a new save-game, that would be great. I've just an idea what is going wrong and I could upload a new 4.0 version without test.

bug 100% isnt fixed just got it on 4.0

Unfortunately the bug is still there. I'm playing the 4.0 version without any mod (vanilla)

Cyborg Zombies wont appear if you use the Mechromany AP and purge all the organic pops

This bug isn't fixed. It's just happened to me on my game and I'm playing on the newest version, no mods. Complete waste of time as I now can't stop it from happening. Over 250 in-game years wasted.

No, it has been fixed (and is neither compatible)!

is the mod still needed in the new game version?:P

@CordialVillain: could you somehow give me your savegame and your mod list (preferably as json)? Evolved has no conflict.

Okay, after some digging in files, I *think* Stellaris: Evolved is the cause of the glitch for me.
My reasoning is that in the the events file in Evolved- there is what seems to be a huge amount of events related to ascensions, including cybernetics. All that said however, I really have no clue, and my capability to tinker with it is non-existent. Another one for the incompat' list?

How long has this bug been occurring? I'm hoping PI fixes it, since this patch isn't working for me. I'd give the save file, but I use just north of 50 mods.

Turns out the mod had an auto fix for my issue, the game just took a while to show it because it slowed down a bit. Psionics is still apparently hardcoded into the game for species changes too, but thank you for being responsive.

@sirjackthereaper: I've an idea. Do you have an official bug report?

Do you happen to have a fix for the psionic species portrait bug? It happens still with a few of the mods I use, and i'm not exactly sure how it occurs?

As a side effect, at reviewing the code, I noticed another logical gap, which should fix some situation stuck bugs like this one:
https://forum.paradoxplaza.com/forum/threads/stellaris-clone-army-not-assimilating-into-cyborgs.1714550/#post-30207130

Found my problem was in "Government & Ethics" where I received some "Ethics Points" (don't know how) which cleared my "Authority" choice (no warning there was a problem). Chose my "Authority" problems solved.

I am tempted to send you my saved game as you offered. But it would also require my word document of the over 300 mods and patches I use. Suffice to say your mod now blows up starting a new game or saved game for me. I will disable it until a later date.

I thought it was a bug with one of my mods when I saw all my fox people turn into humans after becoming cyborgs! thanks for this mod!

Now this is a big boy mod

Never had it happen to me, but its funny that it even happens. Paradox magic back at it again

@EJR: it happens if another empire already did the same before., more details you can read in the official report.

I am actually curious, what is the actual flag that causes this bug? I never once had it happen in any of my playthroughs when undergoing Cyberization, whether it be me or an AI

Doing god's work.

Update: Now with active reverse fix (for save games).