Hmm strange, I've never heard this problem from anyone before, what other mods are you running? Also what GPU?
First let me say that I love the mod. Personally I'm using the 1.9.4 version right now because reasons.
Now for what I'm really here for. I've been encountering a bug of some sort for the longest time with said version of your mod. I will use the stone or whatever its called to add creatures to the beastiary, and every now and then the beastiary just gets completely wiped for no reason. Its kind of annoying, and I was wondering if you have a fix for this you can explain to me.
Thanks for your time.
I'm not too sure what causes this, but anything that interrupts things when saving player data can trigger it, it could also be triggered by other mods as well. The 1.9.4 version is retty old now though but for 1.12.2 I will be overhauling the Beastiary and what not soon making it bigger and better.