M.2 missing after ANY power off

[Kc7vwc]

My M.2 drive is now disappearing from the bios & Windows after ANY power off. A couple months ago it started doing this if my kids shut off my pc suddenly. Then it progressed to driver / OS updates rebooting the machine. Now, sleep mode or just a simple PC shut down and the drive is gone on next power up!

It's a Kingston SSDNow M.2 2280 120GB. This has happened across two Msi motherboards - the Z97M Gaming & the Z97 Gaming 5. My PSU is a SeaSonic X-850. 

When it happens, I can usually do a hard power off from the PSU's switch, wait 2-5sec, power on & it's back. This used to work & would last for days to weeks, until some kind of abnormal shutdown happened. But tonight I did a normal shut down & came back a couple hours later & it's gone. 
I've tried changing all the settings in the BIOS I can find that might relate - Hot swap, Intel Rapid & Quick Connect..  Both HWiNFO & Crystal Disk show the drive as being just fine, with no flags or errors. This is the 2nd SSD I've owned & the other (2.5" Corsair Force GT) is even older & I've never had any issues with it. The Kingston has 6,808 GB Total NAND Writes & 9,779 Power on hours. (Corsair has 8,218 GB Total Writes & 13,564 Power on Hours)

 

Checked Kingston's site, and there's no firmware updates or anything for this model. 
So any suggestions aside from a new SSD?

[Kc7vwc]

One other question - does anyone think this might be an issue with the mobo? I'm hoping to get another M.2 drive soon but I won't if the problem is with the board. 

Since both mobo's had this, I'm thinking it was the drive. But since both Z97s are basically the same thing (just more PCIe) there's a chance it could be a common issue.

[Kc7vwc]

For what it's worth if anyone comes looking later, I tried the Kingston drive in my wife's Gigabyte Z170 board and it found it right off. Powered off & still there. Pulled power cord & still there. No data on drive so can't confirm booting or anything, but it's orders of magnitude above it flat not showing up on my MSI boards. 

Both of those were latest BIOS too.

TL;DR So not sure what's f*cked, but it's my motherboard's fault. Back to 2.5" SSDs.