Asus ROG PG32UQX video input troubles?

[Thunderdolt]

I just connected a third source to my screen and this seems to be causing some issues with the screen. With only two inputs, everything is fine. When I add a third input, the screen becomes very picky about switching inputs.

• The input must be live before switching otherwise no input is detected. If not, the screen will say that there is no input detected even if that input becomes live just a moment after switching. Sometimes the screen needs to be hard power cycled to detect that input.
• When switching to a live input, it sometimes takes a full minute for an image to appear
• When switching to an input, the screen will sometimes stay black, a message about No Signal will appear, and then the input will change back to a working input but with the wrong label. For example, when on DP but switching to HDMI 2, the screen will go black, No Signal will appear, and then the OSD will say HDMI 3 while showing the video from DP.
• Screen doesn't always wake up

All of these issues disappear when I leave only two inputs connected. The two can be any combination of HDMI or DP.

Input sources are 3090s (tried DP & HDMI), an A6000 (tried DP direct and DP->HDMI connector), and even the onboard video from an i7-11700K (HDMI). Have also tried with G-sync on and off, and I've tried switching the same sources between all four inputs. None of this has had any effect, but connecting only two inputs brings it back to normal every time.

I'm not really sure what else to try here. Any ideas? Has anyone else run into this?