Sleep Quirk

I left my machine running last night so it could finish copying files from my old drive to the new one. When I woke up this morning the power light was flashing, its sign it's in sleep mode, but the internal LEDs (GPU, CPU heatsink, etc.) were all still on and I couldn't wake it from sleep. I ultimately had to power it down completely to bring it back up. When I did it booted right to the desktop without going to the lock screen as usual.

Any idea what happened here? How can I prevent this from happening?

This is a clean install on a RAID0 SSD.

I had basically the same problem. I had to shut it down and restart.