Is onAppear and onDisappear in a NavigationView of a SwiftUI app behaving as expected?

It was a bug on Apple's end.

.onAppear() now works as it is supposed to in iOS 13.1 and Xcode 11 Beta 7.

When navigating forwards and backwards to the NavigationView, .onAppear() will trigger.

Starting Xcode 11.2 beta (released 02/10/2019), both methods (including .onDisappear()) are being correctly triggered.

Note that .onDisappear() was not being triggered until this beta release.