Advice on boot console resolution issue

[Christian Kastner <ckk@kvr.at>]

I'm not sure if this is a bug or not, and would appreciate input on the
matter.

Whenever I boot my machine, the GRUB boot menu looks normal, but
everything textual following that (crypto unlock prompts, service
startup messages, etc.) is completely distorted. For example, here is
the prompt to enter the decryption password:

   https://filepost.io/d/wiG25b3pN1

I suspected an issue with the 2560x1440 of my monitor, and indeed: the
problem went away with a 1920x1080 monitor.

Interestingly, the problem also went away once boot was complete.
Switching to a tty with e.g.: Ctrl+Alt+F1 presented everything in order.

Does anyone have an idea what could be going on (bug, or some EDID issue
with my monitor?) and more importantly, how to fix it?

Christian