Premiere and Media Encoder freezing routinely

I'm working on about 10 large sequences (1-2 hours each). exclusively avchd/mp4 files (c100 mk2 files) and legacy titles. I don't have the issue on other projects with different codec media. Only these avchd files that go longer than 30 minutes or so.

If I leave my desk for longer than 20-30 minutes, I return to premiere frozen (spinning blue circle) and have to hard kill the program and restart it (no reboot needed).

When exporting to AME queue, it only get between 20-70 percent the first job and then freeze up in the same manner. But it appears the export continues in the background because, given enough time to finish, the file is done without issue--but only the first, it doesn't continue to the next job. Another interesting thing, is that if premiere is playing a sequence without interruption for longer than 10 minutes or so, it freezes up in the same way but I can still hear audio from the sequence playing without issue, just can't do anything about it till I kill the program and relaunch it.

I've tried uninstalling the whole suite and using the adobe cc cleaner. Updated windows, updating adobe, updated gpu drivers, I also just updated to CC 2018 this morning and I'm still getting identical symptoms. I also swapped out my RAM sticks and GPU to some other spares I had lying around and no difference.

Adobe CC (2018)

Windows 10 64 bit

Intel i7-5820K

GTX 1080 Ti

32 GB DDR4