Hi, I was just going to post something similar.
I posted a few days ago about how "Seated Passengers in 2024 MS Strore" no longer shows my two iniBuilds a300-600s, so I cannot enable seated passengers. I noticed today that all the windows are now empty. Just as your screenshots show. I updated the Universal Installer to the latest version (v1.2.3) but the problem persists.
Thanks in advance for any solutions.