I had a problem with df on a cif mount. I Googled and found a work around. Thought this might interest others so including 2 links.

TL;DR - There is a bug in 5.15.0.102-generic. Reverting to 5.15.0.101-generic solved the problem. I hope/assume this will be fixed in the next update.

https://forums.linuxmint.com/viewtopic.php?t=417371

https://askubuntu.com/questions/1509987/cifs-on-22-04-lts-has-something-chan...