Japanese Input not working in Linux Mint 22, Musescore 4

I'm having a strange issue, Japanese input is not working on Musescore only. Japanese input works in all the other areas I tried (web browser, terminal, text editor). I would appreciate if anybody has any ideas to get this working!

Version stuff:
OS: Linux Mint 22, Arch.: x86_64, MuseScore Studio version (64-bit): 4.4.3-242971445, revision: eb6b367

Steps I followed:
1. Start with a fresh installation of Linux Mint 22 Cinnamon, ran updates.
2. Follow the "input method" instructions to enable Japanese input. (Screenshot attached)
3. Install Musescore by ./MuseScore-Studio-4.4.3.*.AppImage install

At this point, I can toggle between English/Japanese input by pressing control-spacebar. For example, in Firefox, if I switch to Japanese input and type "aba" it will render the Japanese characters correctly. (Screenshot attached). However in Musescore, the Mozc pop-up doesn't appear, and is just stuck in English. Switching between Fcitx and ibus for the input method framework didn't seem to change anything.