There is some heavy discussion on Facebook regarding a downgrade in video bitrate after the new firmware ? To only 2Mbps other than the 6 or 10Mbps that was previous ??  For the advance version.

In custom some people can change the rate, but it will have no effect? Can anyone confirm .

If so and DJI has limited and downgraded it would be annoying

I´ve been a happy P3 flier, over 250 flights so far, but this last update really dropped it. My phantom has worked flawless, over mountains, forests, oceans, have never had ANY problems I cant handle and it has given me 100% everytime. But with the new update I get bad lag on my iPad Mini 3, never had that before, it´s like the image jumps every 2 seconds and lags.. FIX IT!

Also doing a real big job right now and wanted the 2,7k option because I´m filming about 100 different scenes for NHK in japan and suddenly I cant trust my P3..
Early morning today was a real PITA trying to fly 4 laps around a small boat and up to the sky with the image lagging. Thought it was a bad area but switched location and the lag was still there, tomorrow I´m supposed to fly 200m to a river and then spin 3 close laps around 4 people and out over the river again and the P3 doesn´t feel like 100% anymore!

Another bit rate problem is that if the camera starts in video mode on startup, recording video is at 25 Mb/s.  If the camera starts up in still mode, recording video is at 40 Mb/s.  Video is set for 1920x1080 NTSC, 60 fps.  Also, if the aircraft is shut down in video mode, when you restart, it will default to video mode and record at 25 Mb/s.  If you shut down in still mode and restart, video will record at 40 Mb/s.  If the default is video mode when you start up, and you switch to still mode and back to video mode, video will record at 40 Mb/s.  If you have been recording and stop recording and go to review mode and shut down the DJI Go app while in review mode, restarting the app will have the camera in still mode rather than the video  mode it was in before you went to review.

This is not just on my Phantom 3.  It was first reported by a friend and I confirmed his observations, today.  His work-around is just to be sure that he switches to camera mode before recording video.  He contacted DJI and they wanted him to send the aircraft in for service.  Looks like they need to look more closely at the problem.

While this may not address your problem directly, it certainly could be related.