VMware Fixes vSphere 6 CBT Issue
The Patch willl resolve the issue on ESXi 6 Update 1a
Reading a little more into this patch on the Veeam Community Forums, Gostev goes into explain that applying the patch is simply not enough. In every instance a CBT reset is mandatory. The reason for this is that existing CBT maps may already contain issues which result in inconsistent backups.
Performing a CBT Reset
Veeam has posted the following article (KB1113) which lists the steps involved in performing a CBT reset