Hey Ej: Yes I'm using the GoPro mic adapter. As you're well aware by now the issue happens when you plug an external battery source regardless of whether it's an external GoPro battery, a third-party battery or even directly from the wall outlet… The audio is out of sync… The audio is out of sync when camera, mike adapter and external power source are connected all at once and you push record. Now take the external battery out of the mix and the camera records normally. Sadly the work around is combersom and not something you would expect from a $500 set up. The issue was reported in October 2018 according to your own GoPro support hub. I'm getting the feeling GoPro does not have an answer. Mine will be to return the camera soon if not resolved. Too bad. Signed a once happy customer.
