onDisappear called after rotation

Testing swiftUI master/detail on simualator (11.2.1). When rotating detail view from portrait to landscape, everything OK.

When rotating from landscape to portrait, onDisappear is called following a console message: 2019-11-18 14:17:27.902794-0700 combineTS[41908:4781824] Unbalanced calls to begin/end appearance transitions for <_TtGC7SwiftUI19UIHostingControllerVVS_22_VariadicView_Children7Element_: 0x7faa29410200>.

Does anyone know why this is happening and how it can be prevented? I am trying to detect when the back button has been pressed and the detail view is being destroyed so I can cleanup database been used in detailView.