Can you test if these crashes only happen when you play a file with Dolby TrueHD (Atmos) audio? Also test a 1080p file with these audio formats please. If so, try enabling Audio passthrough in the audio settings. Additionally enable TrueHD passthrough. If your TV/AVR supports decoding TrueHD audio, you should enable these settings anyway. Check this.
@sam_nazarko Just out of the blue I’d guess it’s still this. I assume the Plex add-on always uses the seek method that is usually only used when skipping chapters, because when I tested the Plex add-on with TrueHD passthrough disabled, I was also getting a sad face like the OP described here.