That'd at least make sense, this is a (literal) black box. Seriously, my monitor takes long enough to wake that it's at the boot loader screen by the time it's ready.
I found a post on Reddit claiming it's a RAM thing, and I should enable XMP to avoid it. But I've already got XMP enabled so I need to poke around it again.
And also disable the 5 second delay in the bootloader, not like I'm ever using that fallback option.