VMware broke the CBT mechanism for backing up virtual machines

As it became known from KB ( 2090639 ) in VMware ESXi hypervisors, versions from 4.x and up to the current command when calling the QueryChangedDiskAreas to request information about the occupied disk sectors of virtual disks, the return value may be incorrect or completely missing. At risk are all VMs. The size of the vmdk disk that exceeds was less than 128 GB and subsequently increased. What it is fraught with - all backup utilities that use this mechanism (for example, Veeam) can create invalid backups . A workaround is to disable and re-enable the CBT mechanism for all virtual machines.
For the latest information on the topic, subscribe to the KB specified at the beginning.

PS The Veeam newsletter has a link to the PowerShell script to disable CBT on all virtual machines.

What is CBT: Changed Block Tracking (CBT) is a VMware feature that helps make incremental backups. VMware Data Recovery.
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upd: According to TheRealGostev, who instigated all mailing lists - Only those VMs that have increased the disk size after turning on CBT are at risk, and this increase process caused the disk size to “step over” 128GB

upd2: TheRealGostev continues to investigate the problem and publish new data and clarifications

Check backups of your virtualok!