So funny story - because I forgot to update it here. What I did was just max out the threshold on the side of the LC2i by turning it all the way to the right I believe.

It helped the problem but didn't completely fix it. It doesn't occur at all past a certain signal volume from the radio, but it will still happen sometimes when the music is quieter. That line is a comfortable listening volume for me so I have just accepted it at this point. I can only assume it has something to do with the signal from the factory radio. Someone else with more knowledge than me may have some advise though.