KB1790: Veeam Backup Temporary Snapshot
https://www.veeam.com/kb179009.07.2013 · As detailed in the Veeam Backup & Replication User Guide, a snapshot is created on a VM that is being processed by a Veeam job.This creation of this snapshot causes the VM's base disks to be in a read-only state during the job's read operation. The snapshot that is created during this process is named VEEAM BACKUP TEMPORARY SNAPSHOT.
KB1681: VM Loses Connection During Snapshot Removal
https://www.veeam.com/kb168104.10.2012 · Veeam does not remove the snapshot itself, Veeam sends an API call to VMware to have the action performed. The snapshot removal process significantly lowers the total IOPS that can be delivered by the VM because of additional locks on the VMFS storage due to the increase in metadata updates, as well as the added IOP load of the snapshot removal process itself.