Can you test without any custom layouts ? to do that you can rename ~/.config/gmusicbrowser/layouts to, for example, ~/.config/gmusicbrowser/layouts.disabled
Also, could you run it from a terminal with the option -backtrace, and show me what it prints after one of the "Argument "\x{31}\x{35}..." isn't numeric in sprintf at /usr/bin/gmusicbrowser line 540." ?