Using Builtin VMware Agent Backup Policy to Backup VMs causing non snapshot removal and orphaned CTK files

Hi

We have an issue with Backup Exec 2010 R3 using vmware agent backup on a built in full/differential policy whereby the following happens:

• Backup takes a snapshot 
• Backup completes
• Backup does not remove the snapshot taken 
• CTK files remain after manual snapshot removal

The problem is that it is causing come VMDKs to be inaccessible by the virtual machine espcially SQL VMs. They list in device manager but come up as inaccessible "Device not Ready" This shows even before snapshot removal and is down to the CTK files 

Changing the vmx file to ctkenabled:false for all drives and booting the VM fixes the issue but we have to do this after every backup from BExec.

Is there are reason why this is happening? Its seems Changed Block Tracking is not working and need to understand if it is vmware at fault here or Backup Exec