I might have guessed as much . Throw that RPi unit away and rewire back to standard.
With luck the ignition module will still be on the valence, but without the top lead connector (? terminology) in place . Also with luck the RPI unit will just be spliced into the wiring and its removal should still give you the possibility to connect everything back up as standard . If this is not the case I can start by taking a few photos of my set up for you so you can get a general idea
PS I too had an RPI amplifier, and it threw up all sorts of issues , so was eventually ejected from my car and garage with some force.
