PS4 tries to run in 720x480

So my PS4 Pro showed a black screen on my 1080p monitor after the latest update. It works fine on a (also 1080p) TV though.

Before the update, the console worked fine on my monitor. I noticed that the PS4 tries to display in 720x480 on my monitor.

I don't think that the monitor is the problem, because my PS3 and Xbox One still work perfectly with the monitor, and so did my PS4 Pro BEFORE the update.

I tried to reset the resolution in safe mode (the monitor displays the safe mode fine), but that didn't work. Is there a way to fix this?