System hangs after restart with new Vega 64

My motherboard is an Aorus Z390 Ultra.

I'm running a dual boot setup, with Mojave on one drive and Win 10 Pro on the other.

I just swapped out my ASUS strix vega 64 for a reference vega 64 liquid cooled. When restarting from Mac OS or from windows with the amd graphics drivers installed, my system hangs on boot code 92, which is 'PCI Bus initialization is started.'

On windows, with no drivers installed, it restarts normally.

I updated my drivers and my bios but nothing helped. It only boots when the computer is turned off completely (power cut from psu) and turned on again.

I've contacted AMD support, and all they've done is made me install a variety of different gpu drivers. When a driver is installed that has never been installed on the system before, it boots fine. However, if the driver is installed, then I boot into macos, and then after turning off the machine and restarting from windows again, the issue starts again.

I feel the issue is being caused by something in macos, but I can't think of anything.

I have no clue what's going on here, as the cards should be the same, and this issue wasn't occurring with the previous vega 64.

I have four other PCI devices connected to the system, a gigabyte titan ridge thunderbolt card, an airport extreme wifi/bt combo card, and two m.2 drives.

I'd appreciate your help.