Hihi, I saw a lot of people posting the same, sadly the answer you provided didn't solve the problem. So here I'm asking for your help. Im currently playing cisco ultimate modpack, that includes your mod. I was finding the sunbird and when I came close to it it crashed. (Screenshoot attached). I'll provide full logs for my client side and if you need I can look for the servers one

Here's the crash report: https://mclo.gs/euYDs4g
Here's the lastets log from client side: https://mclo.gs/1Rd3Etp
And Here's the lastest log from server side: https://mclo.gs/CKRUIjI

Any other thing you need free feel to ask for it, will do my best to help out

To add to the post: tried removing yongs structure mods, didn't work. The only workaround I found es changing the player data coordinates using NBTExplorer, setting a different XZ position and don't come close to the sunbird spawn

Oh gosh, if removing YUNG's mods didn't fix it I'm not sure what would.

Does it happen with mowzies mobs installed by itself?

Didn't try with the mod alone since im playing in a modpack, but I removed mowzie mob and worked, sadly I can't fight the sunbird, didn't happen with mawfrost tho