If you use a footprint file containing mechanical holes, Flux won't render it as Mounts.

Here's a very long loom recording if you want to understand what this feature request is all about. https://www.loom.com/share/bb1257ff7f674c879f642b90fe44d0c7

Test footprint files are here: https://drive.google.com/drive/folders/1s5laelV_BbyiN8JoZ_N4PP8mDVnhFjJ0?usp=sharing