SwiftUI Master/Detail view problem when Split View enabled

Master/Detail works fine across iPadOS and iOS in fullscreen mode, but when I engage SplitView the Master view will change as I select an object, but never reveals the detail view.

If I go back to full screen, or more than half of the screen available, it starts to work again

UPDATE It appears to be related to .listStyle(.grouped) which I had on my Master view. Removing that has solved the problem completely.

Please share your solution as an Answer and mark it as SOLVED.

SwiftUI Master/Detail view problem when Split View enabled
 
 
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