Haven't got the opportunity to shoot for a few weeks due to bad weather, but using my ASIAIR Plus I noticed a couple of times this lost connection with the default settings you mention.
It never happened with the ASIAIR pro.
I eventually managed to solve this issue by making sure that SkySafari was started AFTER ASIAIR app.
It didn't make any difference with the Pro, and shutting down SkySafari, then restarting or powering off ASIAIR and then restarting it, solved the problem.
Don't know if it's related to the Pro vs Plus or simply a matter of firmware...
I'm looking forward starting a new session, but good weather is not forecasted for a while over there....