set "Better vanilla skin transparency" OFF by default.
Incompatible with "Ears" mod:
There is a problem with "Ears" Mod. It uses transparency as a storage for wing data. When "Better vanilla skin transparency" is ON, these pixels appear transparent and wings dont work:

With "Better vanilla skin transparency" OFF, everything works as it should:

Does another mod also do this?
no

This issue doesn't just affect wing rendering, it also breaks Ears Mod's erase regions.
I also found an open issue on the Ears repo talking about this: unascribed/Ears#164