Hello!
From what I can tell, the content should not be clipped under the vertical bars, as the only time that is not visible is when Reduce Transparency is enabled in Settings. Otherwise, it has two behaviors:
No background when there is no horizontal scroll area
A partially translucent background when there are horizontal scroll areas, so clipping content would be noticeable
Refer to the Tech Talk "Raise the bar with iPhone Duo" timestamp 10:52.
Hope this helps!
Topic:
SwiftUI
SubTopic:
iPhone Duo SwiftUI Q&A