Brumball

I'm having a bit of a weird thing happening. If not an actual 'issue'. What seems to be happening is that every time i start the game (or load a save?), FNIS (or maybe TK Dodge/TK Hitstop both of which i use and are working properly) is generating Meshes/~AnimationDataSingleFile.txt in the Overwrite folder. The exact same .txt file has already been in my fnis - output mod for a while now, so i just keep deleting the newly generated one rather then merge and replace. Any ideas what is causing this and how to stop it?