Sure, but you can always stop and restart with the internal GPS only. Advantage, your log files are clean and the configuration well defined. If you switch sources there must be some documentation in the log as well. I am not convinced such autoGPS is really something I want.

If you are disconnected from the source of both position and traffic data you won't get any traffic warnings anyway. 

Obviously the commercial decision is one for you and the team to make, but I think it would be very useful to have, and also may pre-empt future problems when more and more people start using a (potentially) wider variety of devices, there are more likely to be problems. Naturally it is up to whatever 3rd party manufacturer to fix the problems, but SD would at least mitigate the effects.

Samsung Galaxy Tab A8 – Android 11.0 & SD 4.1.1.0

We have to be sure this is a real problem for a decent percentage of users to make it worth spending the resources on implementing either.

I suppose I imagine a banner similar to (or incorporated into) the one which tells me that the third party device is offline/no longer available and that there had been reversion to internal GPS. If the 3rd party device is detected again then perhaps a banner to say it's available, would you like to switch back? If yes then switch, if no then don't switch and no further prompts. This way if it was an intermittent thing, the user could try it once or twice but if it became annoying/distracting because it wasn't working right, then a 'no' answer would silence further warnings.

Some way of selecting it manually whilst in flight would also be good, perhaps just on the main menu either within or below 'setup', a 'Position source' or similar with an option of choosing available devices.