I have this error on starting server: https://pastebin.com/v2PCp3cD
Im using fabric loader 0.12.8, java 16 and curseforge launcher

It seems to be fixed, the problem occurs only at the first launch

Fixed on 1.18 by the above commit (I hope). I'll probably backport the fix to 1.16 later, but I'll be dropping support for 1.17 since porting to 1.18 should be easy for most mods.