To be honest, it wouldn't surprise me. Perhaps you have a version from the Steam Workshop installed and one from here, or perhaps you only have the versions from here installed and one of the catsuit legs is a remnant from an earlier version that wasn't removed because you'd simply extracted a newer version of the Felin mod on top of the older one instead of removing the old one before... but I'm just wildly theorizing here. Nice avatar, by the way. Edit: I looked into it some more. Both base mod and cos+ have spycatsuitlegs items, but I get no issue from them. This is probably because they have the exact same relative path and thus one can safely completely replace the other. Besides the capitalization of the word "common", the files are identical. I don't know why this doesn't work for you.
Alright, so I believe I found the obvious solution to a silly problem that I should've noticed right away- I needed to update Felins. Updated, and boom. No issues. Now I feel stupid. And thank you! Literally. I couldn't have had this avatar without your work.
Love the mod, just curious if theres a way to hide the underwear under neath? When wearing the bikini bottoms and bunny top, the red of my characters default underwear shows a little