What is using my Snapshot Space (3.27TB Missing)?

I seem to have lost 3.27TB of space on my SAN and I cannot figure it out.

I'll keep it simple for now:

3TB volume, thin provisioned, 2.34TB in use.

Snapshot space is set to 150%.

3.27TB Snapshot space in use.

Number of snapshots = '0'

My question is - what could be using this space (see screenshot)?

I use VEEAM for backups of the Servers within this volume, but nothing is currently running.

I cannot delete snapshots, as there aren't any - I can create new snapshots fine and delte those, but this chunk of space remains.