Hi Jecel,
I noticed the same on my Qwertz (German) keyboard after switching from Windows to Ubuntu 22 (Gnome). On my keyboard/input method, I have two options to work with the dead key:
1. Press the dead key followed by a space 2. Press the dead key twice
While the first one causes exactly the problem you mentioned, the second way results in a regular circumflex for me. Does it work for you, too?
I'm investigating this further and am working on a possible fix.
Best, Christoph