I know about the issue on Github and was thinking it's maybe something <3.0.2 specific (even though I really don't know why it would happen this way) and I'm curretly trying to install the new package on some of my other Sailfish OS devices with older SFOS versions. Still, it seems to work with 3.0.1 for others, weird.

Can you maybe try to run it from terminal and send me the output (here ore privately - based on your preference) ? Just launch the terminal and run "harbour-modrana".