2 weeks ago
There has been an update to better support the interference that is being experienced when using the Pro 3.5 Mic Adapter with Wi-Fi enabled. After further investigation, we were able to identify the audio interference you referencing is linked back to the external microphone that is being used.
In order to most effectively record while utilizing Wi-Fi, you will need to use an external mic that has a stronger shielding within the device such as a RØDE video micro. Given the vast amounts of external mics on the market, it is difficult to identify which third party model has this stronger shielding. I recommend further researching this specific specification when investing in an external mic.
Here it is, May 14, 2019 and the adapter still is not available and there is still no explantion as to why. I have one on backorder at B&H but I'm not holding my breath as to when or if I'll be getting one. The lack of response from GoPro with real answers is making me regret my purchase.