I'm now of the opinion that NVME is still bleeding edge compared to good old reliable SATA III.
Yep, pretty-much. Along with thermal limits / throttling, like we've never seen with SATA.
I was having issues with one of my DeskMini H110 rigs, and an Adata XPG SU8000 3D MLC M.2 PCI-E NVMe 128GB drive. I was leaving the PC running (Windows 10, so it might reboot due to automatic updates), and sometimes I was coming back to the PC, and it had booted Linux, which is the default OS on my secondary SATA6G 2.5" SSD in that box, that would be the logical drive to boot off of, if it can't find my NVMe SU8000 M.2 drive, which is set as the default boot option in the UEFI.
Although, I found out later than the UPS it was plugged into, had a failing battery.
Just for S&G, I'll try waking up that machine after a few days in sleep mode, see what that gets me.
Edit: Apparently, I'm suffering with a similar issue with this particular DeskMini box. (My other DeskMini does NOT have an M.2 PCI-E SSD, just a 2.5" SATA SSD.)
I went to the machine, and the HDD light on the front was blinking in a regular, repeatable pattern (but no error counts, just repeated blinking). I turned the monitor on, moved the mouse, hit the keyboard, no video output.
I forced shutdown, then powered up again, and it booted right up into Windows 10. So whatever it was, it's not currently happening.