UR22C output only in one channel


I just purchased the UR22C. I’m recording with a mic in line 1 and a guitar in line 2, and the system is connected to my iPad through a USB 3.0 to lightning adapter. The unit works fine with my regular recording software (GarageBand), and there’s no need to press the mono button. However, I do have issues when recording to video, since the vocals come out of the left channel and the guitar out of the right. I expected the mono button to resolve this, but unfortunately this was not the case. Do you have any suggestions? Are there other settings on the unit that I need to adjust? Thanks!