This issue is documented in CNV-13500.

The RN states: In some instances, multiple virtual machines can mount the same PVC in read-write mode, which might result in data corruption.

Per Adam Litke, this issue is closed as "Won't Fix" but still is a known issue.

The workaround is to avoid using a single PVC in read-write mode with multiple VMs.

Catherine Tomasko requested that if this issue has no plans of being fixed, that we need to make mention of it in the docs as an expected behavior.