That fantastic feature of web apps to reload themselves after they have timed out is at least partially broken on iOS 12.2 that came out last week.
Specifically for web apps that you’ve saved as home screen shortcuts. My initialy impression was fantastic! They now let the pages stay active in the background so they don’t reload every time you go back to them. Which is awesome, you can switch to another app and then switch back to the Xojo web app and it doesn’t reload back to the beginning every single time! Unfortunately that seems to come at the price of being stuck completely at the “this app has gone offline” message sometimes, but not all the time.
If you come back to the app during some period after the session timeout, but before some other unknowable time, it will show you that error message but then reload in a second or 2 and all is well. If you leave it a little longer than that however you get stuck at the this app has gone offline page and the reload no longer works. Then if you want some hours more it will start from scratch and reload you from the beginning.