I can't seem to find the same issue anywhere, and it seems very weird to me. I'm going to give a lot of background to help explain it. My computer has 2 WD SN 850 1TB drives installed in it. One of them has Windows 10 on it and another is just for storage, I know which one is which. I also have a 4TB HDD installed for media storage. I wanted to remove one of the SN 850s and replace it with a new Acer Predator 2TB SSD. This is an easy 3 minute install, but when I go to boot it takes me to a Windows recovery screen that has 4 options. One option takes you to the BIOS, the other 3 just reboot and take you right back to that screen. This includes when you press F1 to enter recovery mode, just reboots and goes back to the same screen. My initial thought was that I pulled the wrong SSD out. I removed the other 1TB drive and reinstalled the one I originally pulled. This time I got a message from the BIOS indicating there is nothing to boot to on that drive. This confirms to me that the second drive is not the Windows drive. I tried flipping up which onboard mother board slot I put the boot drive and which one I put the new 2TB drive, but the other combination doesn't work (I have 2 PCI 4 m2 slots built onto the mobo). Finally, I just put both original drives in. It will boot every time as long as the 2 original SN850s are installed. If you remove either one, it will not boot.
Some things I think people will mention are the boot priorities in the BIOS. It is not that. It is booting to the proper SSD as far as I can tell. When the Windows SSD is in there, it goes to a recovery page. When the other one is in there, it goes to a BIOS, not boot file page. Another thing is that maybe I had them in a RAID or somehow part of the boot files are on the second drive. This is not the case. I have completely formatted the 2nd drive and erased it as a volume on disk management. As far as I can tell, Windows shouldn't even know it exists when it isn't plugged into the mobo.
So, this leaves me where I'm at. I can use my computer as long as I have 2 specific 1TB SSDs plugged in. Why though?