New Gigabyte board booting slowly, white cursor top left corner? BIOS Update FTW

I put together a new build this week and noticed it was taking its sweet time to boot (Gigabyte B560M DS3H with 10th Gen i5 and SATA SSD) whether from restart or shutdown. Sometimes 30 seconds, other times upwards of 5 minutes it would sit with a while line at the top left corner. Generally felt clunky and not new pre-Windows-loading (worked just fine once Windows was up). 100% fixed with BIOS update from Gigabyte. We don't usually update the BIOS unless there's a specific issue going on... I had ruled out connection issues with the SSD and since the delay was occurring before the Windows wheel, and the splash screen took seconds to appear (vs. milliseconds), I presumed it was something on the motherboard-level.

Later that day, a CyperPowerPC came in with the same issue, white cursor line at the top left and not booting up all the way... but sometimes it did boot up okay. Asked if it was a Gigabyte board. Lo and behold, t'was a Gigabyte B550 UD AC running a Rzyen 7 with an m.2 SSD.

Unfortunately, CyberPowerPC uses their own OEM boards with their own BIOS. There was no BIOS update available from them (which took us a several minutes to figure out since this particular motherboard wasn't listed on Gigabyte's site). We ruled out m.2, RAM, PSU, or CPU issues with our usual tests.

The workaround we used was to disable CSM booting. That brought the boot time down to 20 seconds with no USB storage devices plugged in, or 30 seconds if we did have USB storage devices plugged in. USB boot was already disabled/not an option, interestingly (I don't recall which, now). Advised customer to unplug USB storage devices if it takes a long time to boot, and to reach out to CyberPowerPC for an updated BIOS file.

We figure the motherboard was getting lost/confused picking a device to boot off of, or whilst inspecting storage devices for boot files.

Weird things we encounter in computer repair.

This is also my first Reddit post... not sure if this is in the right subreddit... I'm hoping to find a place to post our "we came across this really ridiculously weird issue but we fixed it and this is how" stories. Hopefully not all of them will end up related to Windows "You made me ink!" moments or AMD GPU drivers. ;)