I'm using a shared project
Prism unity 6.3.0
My ViewModel implements INavigationAware but when coming back from a modal via the navigationService.GoBackAsync(); OnNavigatedTo is not being fired
Try with PCL and see if you have an issue. I always stay away from Shared projects due the way classes are included in the assemblies and they don't play nice with EventAggregator when using modules.
Actually I did try it with PLC and it did work. that's why I specified that i'm using Shared : )
Xamarin Inc., as a wholly-owned Microsoft subsidiary acting as a separate legal entity, adheres to the Microsoft Privacy Statement: Privacy & cookies