Using the procedure browser, in Gimp 3.00RC1, I see these messages in the console:
(procedure-browser:1040818): Gtk-WARNING **: 22:36:28.918: Failed to set text ‘Input layers mode, when non-interactive (0=none, 1=active, 2=all, 3=active & below, 4=active & above, 5=all visibles, 6=all invisibles) (0 <= input <= 6, default 0)’ from markup due to error parsing markup: Error on line 1: Entity did not end with a semicolon; most likely you used an ampersand character without intending to start an entity — escape ampersand as &
My money on the culprits being these two:
And while you are at it, you can drop the final s on visibleS 