The closest I could find on this is the warning documented here -
Reason: "The storage pool is running out of capacity."
Recommended Action: "Add additional capacity to the storage pool or free up capacity."
Though it does not show up as warning for you, it is worth checking this warning health status - threshold breached in the Persistent memory health management document. It says -
Reason: Persistent memory devices track various thresholds, such as temperature, NVM lifetime, and/or energy source lifetime. When one of those thresholds is exceeded, the operating system is notified.
Recommended Action: Depending on the warning threshold breached, it may be prudent to replace the persistent memory device.