Nomad CSI directory constantly growing

The following directory on the nodes is constantly growing (/opt/nomad is my data_dir):
/opt/nomad/client/csi/node/nfs/per-alloc

It relates to the allocs that use the NFS CSI driver, I guess.

Some allocs in that directory are very old and not relevant any longer.

Is there a way to cleanup that directory to regain the disk space?

I currently use Nomad v1.6.0.