The schematic has a feature to swap components. To do so, select 2 symbols, right-click, and select the Swap operation (with the shortcut S).
But the shortcut S creates a new Hierarchical sheet.
This overlap could work if a check to see if something is selected when using the shortcut S since the swap should not work if nothing is selected.
If you cannot get on to Gitlab to read the comments; the reason changes haven’t been applied is because those changes will mess up personal custom hotkey alterations.
Devs are waiting 'til Kicad 9 to fix the problem.
Meantime, change Sheet or Swap hotkey to something else.
There is also a problem with the double use of the P hotkey in the schematic.
Oh, nice @jmk . That’s a really good and complete answer, thank you. I can use the functionality, it is just the shortcut that is not working. But since this is already being tracked, it is all good. Thanks.