During Virtual Machine deletion, it might generate some orphan PMem regions. PMem garbage collection will take care of the orphan regions and free up the capacity. During the garbage collection interval, the orphan PMem regions' capacity will be calculated into the filesystem overhead category. The garbage collection interval is 5 minutes.
After deletion of a Virtual Machine with virtual Persistent memory, either with vNVDIMM or with vPMemDisk. There is a possibility that the size of the used PMem capacity of that Virtual Machine is counted into the PMem used filesystem overhead in the vSAN Capacity UI.
After around 5 minutes, the PMem space will be freed and the filesystem overhead shown in the vSAN Capacity UI will back to normal.
After the garbage collection interval passed for the Virtual Machine deletion, click the 'refresh' button on vSAN Capacity UI, the PMem filesystem overhead usage will reduce and back to normal.
No workaround available.