I have not opened a case with technical support since I have solved the problem by stopping the VMs and moving them cold.
I'm also curious if someone has had the same problem with a QuickMigration of a Windows Server 2012 R2 VM.
The error when doing the QuickMigration is this:
Powering on VM Error: Module 'CheckpointLate' power on failed.

The source server is an ESXi 6.0.0 build: 3620759 and the destination server is an ESXi 6.5 U2. The Veeam version is the last one: 9.5 U3a.
The two ESXi hosts are not associated in any virtual center.
I have been looking for the Veeam KB with the error and I have not found any information.
Thank you!
Xavi.