[iOS][Shell] OnAppearing called twice

[jfversluis]

As reported below, OnAppearing seems to be called twice when using Shell. I think it's unrelated to the other issue described, so opening a new one. I suspect there might be an issue for this already?

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@jfversluis
I just have tested it in my test repo (the one I attached above).
The crash seems to be fixed, however the OnAppearing of the LoadingPage.xaml gets called twice if use

// Navigate back in LoginPage.xaml
await ShellNavigationManager.GoBackAsync();

Here is the output

2021-10-05 18:37:44.968532+0200 _Issue13476.iOS[4943:95336] LoadingPage: OnAppearing called  <-- First visit
Thread started:  #5
[0:] WillShowViewController 11639729
[0:] WillShowViewController 1315972608
2021-10-05 18:38:34.405345+0200 _Issue13476.iOS[4943:95336] LoadingPage: OnAppearing called <-- After GoBackAsync();
2021-10-05 18:38:34.473481+0200 _Issue13476.iOS[4943:95336] SecTaskLoadEntitlements failed error=22 cs_flags=200, pid=4943
2021-10-05 18:38:34.473737+0200 _Issue13476.iOS[4943:95336] SecTaskCopyDebugDescription: _Issue13476.iOS[4943]/0#-1 LF=0
[0:] WillShowViewController 11639729
2021-10-05 18:38:34.546006+0200 _Issue13476.iOS[4943:95336] LoadingPage: OnAppearing called <-- After GoBackAsync(); (second call)
[0:] WillShowViewController 1384107971
[0:] WillShowViewController 235358035

And here the updated test repo:
https://github.com/AndreasReitberger/XamarinFormsShellTestRepo

Originally posted by @AndreasReitberger in #13510 (comment)

[jfversluis]

Also see: #6919

[AndreasReitberger]

@jfversluis anything new on this one? Would be awesome if this could be fixed with the next SR 👍
Thank you!

[jfversluis]

Unfortunately not, if you have the possibility feel free to look into it :)

[aspeckt-112]

Hi.

My apologies if I'm attempting to discuss this in totally the wrong place, but this still appears to be a problem in XF, as well as being a problem in MAUI on .NET 7.0.203.

The problem seems to occur if you push a modal page (for example, an authentication page) from within OnAppearing of the first page in the Shell.

I'm happy to produce a sample and log an issue in the MAUI repo if the team isn't aware of it. But from searching around the web I found this Issue here, but not one in the repo there, hence why I'm commenting here.

Thanks.