On Restart HDD Doesn't Load in Bios

[Hello World Hey There Universe]

Ok whenever I power the pc down then start it up everything's working perfectly, with no issues at all. However if I happen to restart the pc and "only if I restart it" though the main hdd with OS doesn't load in bios anymore.
Specs:
OS - Win 8.1 Pro
Motherboard - Asus TUF Z270 Mark 1
Bios - Version 0801 Latest
CPU - Intel i7-7700K 4.2 GHz
Ram - x2 8 (16) Gigs DDR4 Corsair Extreme
GPU - Gigabyte Geforce GTX 1060 6gb
HDDs - (OS) Western Digital Black 2TB 7200rpm Sata (P1)
Hitachi 500GB 5400rpm Sata (P2)
Disc Drive - HP DVDRW (P3)
PSU - Corsair CX750M

Current Bios Changes: disabled CSM, OS set to UEFI, Disabled unused sata ports
Things already tried... cleared CMOS, Connecting only main HDD, Resetting Bios Settings etc...

 

[Hello World Hey There Universe]

Ok I just discovered a weird workaround to the issue. I'm assuming it actually has something to do with some compatibility with the power supply somehow? (However I set the sata port to "Hot Plug" problem solved)! Perhaps it wasn't getting powered right away when restarting for some reason don't know.