When a MusicTransition (or multiple MusicTransitions) are copied from one MusicSwitchContainer to a different MusicSwitchContainer, the SourceContextObject or DestinationContextObject will update in Wwise to "Any" if the original objects are invalid in the new hierarchy. However, these objects are still referenced (by name and by GUID) in the WWU file.
If the user saves, closes out of the project, and reopens the project, integrity issues will print saying the MusicTransitions are technically invalid, resulting in the MusicTransitions being deleted.
This can be avoided by setting the SourceContextObject and DestinationContextObject upon copying the MusicTransitions, but it is confusing to identify this, since the Authoring tool visually sets the SourceContextObject and DestinationContextObject to "Any"
This is something I come across in my work, when I copy the structures of extremely large MusicTransitionRoot objects into a new MusicSwitchContainer - with the intent of consistent structures. Sometimes I don't get to specifying the SoruceContextObjects and DestinationContextObjects in one sitting, so reopening the project could result in a lot of lost work.
Wwise 2021.1.6