I expect the issue is here:

likely related to #38
crash-2024-08-25_22.58.31-server (2).txt

initialize is called on the new baby, which would trigger a potential mounting of a chicken, which could cause the same dismount code. ideally you should pass a ZombieEntity.ZombieData. no need to set the baby state as its set via the entitydata you feed in

Hi, thanks for the report! You're totally right, I'm doing a safety check for the first baby zombie only, but the other ones can also try to mount chickens first. I will pass a ZombieData as you suggest, this seems to be the perfect fix

(and thanks for reporting the malicious link, I reported it to Github)