This is a project I need to lay to tape (client’s requirement). I thought maybe it was just showing up in the previews, but it is definitely noticeable on tape too.
This seems like an awful simply solution, but I had a similar issue when 1st using the ioHD. Had audio fine but I had color bars every time I went to edit to tape. Turns out in FCP audio/video settings under the A/V devices tab there was a check in the “Different output for Edit to Tape” box. I had “None” under video output and “Default” for audio output. Alas audio but no video, and I felt like a fool for searching for so long and realizing i just needed to uncheck a box. I honestly didn’t know that box was there. I hope that helps or didn’t waste your time.