Alex, since my post, the hotfix was inadvertently deleted.
You probably missed the red error "The feature (Plus/Hotfix_WrongOverlappingBarsWarning) does not exist" at the top of the download page, and downloaded the main 2.9 Plus build.
However, coincidentally we integrated this fix earlier today and it will be available from version 2.9 Plus b1722, overnight (providing there are no unexpected build problems).