It's a bit nerve-racking because you get a message that your boarding group window has expired and that's what shows up on your phone from that point till you actually use it. I had boarding group 90 something yesterday with estimated return time of 5:30. We took the skyline to HS just before 2 and our group got called while we were on it. We did TOT which had been down on our HS day, then returned to Epcot where I saw the expired boarding group window message. I had my screenshot ready to show the 5:30 estimated time, but we had no trouble tapping in. That "your boarding window has expired" message is an unnecessary stressor that they should get rid of. I'm sure I'm not the only one who panicked a bit when seeing it. I must have missed it here if others mentioned it, so just giving a heads up that it doesn't actually mean you can't board.