UISplitViewController Memory Leak
Tested with Xcode 11.5 + iOS 13.5.
Tested with Xcode 12.0 beta 1 + iOS 14.0 beta 1
Sample Project
The MasterViewController has a Details, selecting one will show the corresponding Detail.
Regular Width
On regular width, everything works as expected, there is only ever 1 DetailViewController alive
Compact Width
On compact width, the first DetailViewController is never deallocated, when switching around, there are always 2 DetailViewController alive.