Hi Greg,
agreed with Andreas go ahead and file SR to VMware Support ... in the meantime can you try following:
1. If the issue is reproducible try to disable CBT in affected VMs and test again what happens when snapshot is deleted.
For disabling CBT follow this KB:
2. Verify if affected VMs have vShield/Guest introspection driver installed as a part of VMTools install if its true remove that driver and test snapshot deletion again.