I have this issue also but only about 15 degrees. I suspect the dual speakers on the back of the iFly have magnets. I take it in and out, so I have been thinking of a temp note sticker to take it in and out with the unit to remind me.
I use the iFly 700 in my Archer with a yoke mount on the left side. I have not seen any compass error but will pay close attention during the next flight.
The deflection does not occur with the unit powered off.
We can't seem to duplicate this in our office or airplanes. Give us a call so we can troubleshoot this further.
Mine changes the compass too. Its only 5 or 10 degrees depending on what direction you're heading. It is mounted with the windshield mount right next to the compass and I expected some issues because of that. There isn't anywhere else to put it in the 175. The panel is pretty full. If I unplug the unit the compass moves and plugging it back in moves the card back. I don't think its the speakers though I could be wrong..... Frank