VMware acknowledged a known issue (KB2136854) within ESXi 6.0 and 6.0 U1. CBT looses the information of I/Os during snapshot consolidation. The main backup isn’t affected but all data written during the consolidation task are missed.
ALL CBT incremental backups are potentially affected.
VMware currently has no resolution.
Update 25.11.2015:
VMware released a patch for the CBT bug.
VMware ESXi 6.0, Patch ESXi600-201511401-BG: Updates esx-base (2137546)
