At some point, appimages do not launch anymore when executed in Thunar (double-click, right click execute), but will immediately launch in Dolphin

When using an appimage (in this case Onyx, a rhythm game file converter), Thunar will at some point in the future become unable to launch/execute this appimage and do nothing. If I open the exact same appimage location in Dolphin, and try to launch the very same appimage, it will still work like it used to through Thunar.

I have no idea what could be doing this but I felt it was important to report.