An update on mp4 files causing explorer to freeze. Apparently all files do not cause a freeze. Some work as intended, some do not. However, I can go into MPC-BE and go to quick open file and then change the extension from mp4 to mkv. Upon doing that I no longer have any freezes when trying to access the files that previously cause a freeze. Strange.
I had random freezing issues with my 1809 install last week but they cleared out two days later so I assumed it was Defender being a problem.
I don't know if I am unlucky or just having a bad day but my PC just shut down twice out of nowhere, no GSODs, nothing. Keep an eye.