I had Plex running via Docker, and the Plex configuration/metadata stored via NFS on my NAS. For quite a while seeking would be intermittently slow, or plain crash the Plex server requiring a restart of the container. Other weird issues as well.
Finally I had enough and did some debugging and searching, and found that Plex uses sqlite in a way that is not compatible with networked storage. So I moved it to an iSCSI volume, mounted as a regular drive on the Docker host and it's been rock solid since.
But yeah, didn't expect that.