After updating to 5.6.0.286, Plex perodically crashes while playing movies and/or TV episodes. The crash report has been submitted. Also, when in other apps, a system error dialog periodically appears as well (drilling into the error dialog details a NullPointerException). So, it appears the issue is with a background process.
The error occurs on multiple server versions:
SHIELD - 1.3.4.2385
Synology - 1.4.1.3362
I am seeing this also. I can provide logs if necessary but will need to remove my external IP, would be useful if the default logging had an option to remove personal information like that.