The installation of the VMware patch to fix the CBT issue found in ESXi 6.0 is not sufficient and you should perform also the CBT reset for all VMs to guarantee consistent backups.
This additional step is required since existing CBT maps may contain issues with the result of having future full backups inconsistent.
Reset CBT
Before proceeding make sure you don't have any snapshot in the VM you are processing.
From vSphere Web Client, right click the VM to process and select Snapshots > Manage Snapshots option.
Check no snapshots are present then click Close.
Right click the VM and select Power > Shut Down Guest OS option.
Click Yes to confirm.
Right click the VM and select Edit Settings.
Go to VM Options tab and select Advanced section. Click on Edit Configuration button.
Set ctkEnable value to false.
Set the all of the scsi0:x.ctkEnabled values to false then click OK.
Click OK to save configuration.
Under Related Objects section, click the Storage where the VM is stored.
Browse the storage and click the VM folder to access the files. Select all the -ctk.vmdk files and click the X icon to delete selected files.
Click Yes to confirm.
Right click the VM and select Power > Power On option.
From your backup solution, rerun the backup or replica job to re-enable CBT feature.
Or you can download the powershelgl script form the Veeam forums to fix that w/o powering off the vms
Yes, correct.
For large environments the use of the script will speed up the overall process.