Hi
I also had this issue and it has been confirmed that this is an issue with the EU firmware. The first WiFi Lock is weak and when the landing gear is retracted it interfears with the signal. Due to the EU firmware on 700mhz it takes a while to siv through and the find the connection. Having said that the second connection is stronger and no problems seem to manifest.
This is still not great and following complaining to Yuneec EU I was told a software fix is being looked at but this issue has been around for s long time, with no resolution yet.
However, I have found that if you wait for the inertial connecting to be made, before starting the motors and taking off, press system information on the ST16 and go to the bind screen. This disconects the camera and RC, then from the bind screen select the camera and press bind. Once this has been done press return to go back to the flight view on ST16. You should find that the camera is already connected or connects in a few seconds. This should then mean the first weak WiFi connection has be replaced by the second stronger connection. Now your ready to take off and fly!!!
I have found this method to reduce the disconnections dramatically and I have only experienced 1 disconnection in the last 10 flights using this method. Try it and let me know how you get on, it seems to work well for me!!