One possibility (perhaps, maybe) is that your Rosetta is picking up a Wifi signal from somewhere else when you visit and, therefore, your PAW is not actually connected to your iPad any more. On the way out, because there are no aberrant Wifi signals for it to connect to, it behaves itself but at the turnaround airfield etc it may connect to something else.
I only say this because the other day my iPad was locking onto a local Wifi and, therefore, my PAW wasn't connecting to my iPad and SkyDemon. I realised what was happening and just went into Settings and Wifi and 'clicked' on my PAW Wifi and all was well for ever after.
Of course, I may well be talking coomplete and utter bolleaux and it might be far more complex than that but it is a really easy thing to check. Just make sure your Wifi is connected to your PAW before telling SD to navigate.