I had a similar issue with my PCR keyboard with an EV5 pedal, which sends a CC11,127 whenever I change channel on the PCR. (The default value for CC11 is 127, not 0 as it is for most CCs, and the PCR is a bit strict about this.)

In the A4, CC11 is mapped to Performance Parameter E, so if turning that performance knob back to zero restores normality, then CC11 is the culprit.