Multiple monitor support is broken

[Hampoon]

Hi, I recently got a Pi 4. I don't have two monitors that are the exact same model but I couldn't test it but,

When hooking the Pi up to a 1080p and 720p monitors (of different sizes) the one plugged into the secondary monitor port just puts out a rainbow screen. I also tested it with the 720p monitor in question and a different one (also different sizes) and I got the exact same result. I have tested this on many operating systems using BerryBoot. This is not a defect with any of my hardware. I verified this by writing Raspberry Pi OS to a different microSD card and booted from that and the dual-display mode worked flawlessly. Thank you for looking into this issue :)