AnimBP keep getting corrupted

Hello !
In my project I’ve got two AnimBPs which derive from a custom C++ AnimInstance class, and they get regularly corrupted (probably when I make changes to the c++ class but I’m not sure exactly when it happens). Today it happened once again, both of them got corrupted when I opened the project, I deleted them and created them again, and now the engine even directly crash when I assign them to my character BP and compile it.
Is there any caveat I have to avoid when using this setup ? I’m no expert with the engine but I don’t think I did anything wrong. It’s a shame because I don’t care much about animation lol.


After days of searching and bugging a lot of people on the unreal discord, the only advice I found to never, ever change a c++ header in Unreal.

I actually have found that advice to be false, except for with animation instances. You can modify most c++ classes without issue, but Animation blueprints just self destruct if you modify an underlying class.