I'd say that's a smoking gun!
You're effectivey running a 2.4GHz FPV (digital, but still, really close and realy loud) with 2.4 Ghz control. 2.4 doesn't play well with 1.2 because of harmonic spurs. If the center freq of your camera is at full power and mere inches away, the receiver is going to be deaf to anything your control transmitter might be saying 100-200 ft away.
You can switch to onboard recording, but if you want to watch while you fly, you'll likely need to add on an analog transmitter (probably at 5.8Ghz).
It would be nice if the Gopro supported 5.8ghz Wifi, but I've seen nothing to indicate the radio is built into the camera -- if it is, and the camera and receiver (your phone) can both be forced to use the 5.8 wifi, the interference will go away (assuming it still works at range)