USB-C DP alt mode suddenly stopped working

I have used my FW13 12th gen with an external monitor (4k 144 Hz) ever since it was released. I have been using the same USB-C to DP 1.4 cable the whole time.
A few days ago the monitor was still showing up in system settings (Arch Linux Kernel 6.8 with KDE 6 and Wayland as well as Windows 10), however did not display anything at all.
I tried a different USB-C to DP cable and got the same result on all four ports and the TB4 dock I have been using for years.
Updating BIOS from 3.06 to 3.08 did not change anything.
The monitor works fine if I use the HDMI expansion card however I would much prefer the old solution. I have yet to try the DP expansion card with a DP cable.

Has anyone had a similar issue? Maybe there was a borked FW update?

Since it’s happening in both Linux and Windows, it has to be a hardware-based error.

As I understand it, the HDMI expansion card takes the DisplayPort signal and does some fancy conversion to produce HDMI output. I’m not certain of my information, but if that’s the case, then that suggests that the DisplayPort expansion card is the problem.

I’d recommend contacting Framework’s support people to confirm that. Maybe they have other tests you can try.