Writing to mounted cifs share from container taking up space on host machine

I have a cifs share mounted to my ubuntu server e.g.
/mnt/servershare

In my container I mount a sub directory e.g.
/mnt/servershare/containerdata

My issue is that as I write to this directory from my container it works great but it seems to be confusing the host file system because

/dev/mapper/ubuntu–vg-ubuntu–lv

Grows in size with every file I write to the shared directory from the container. To make this matter worse, as I delete the files on the shared drive, the host does not pick up on this so /dev grows but never shrinks in kind.

This obviously presents a problem because Ubuntu thinks it’s run out of space but it hasn’t.

I can’t figure out what I’m doing wrong, but obviously this isn’t desired behavior.