sounds similar to my issue → PLEX movie issue - CPU death spiral
So far it seems it happens when certain movies are trying to be played, or more precisely when the metadata is accessed on these “bad” movies (playback will call the metadata endpoint before playback) There is virtually nothing in the logs on this, it just consumes all the CPU and leaves the server unresponsive. Your issue could be different, but if you have remote users their persistence on trying to play a certain title could bring down your server. Refreshing the metadata on the entry seems to resolve it, but its very difficult to identify with nothing to go by in the logs.
