I also experience this issue. Was not there in 19.10 for me either. It's ONLY when setting one of the monitors to portrait mode.
Currently I have to use a workaround, running ARandR or "nvidia x server settings" after login to set the displays. But I can't save the settings to make them persistent.
It would be nice to be able to use the monitor.xml to make the settings persistent.
I also experience this issue. Was not there in 19.10 for me either. It's ONLY when setting one of the monitors to portrait mode.
Currently I have to use a workaround, running ARandR or "nvidia x server settings" after login to set the displays. But I can't save the settings to make them persistent.
It would be nice to be able to use the monitor.xml to make the settings persistent.