Standard shortcut and manually specified one conflict on the same action ("key sequence is ambiguous")

Can't tell. Either it is already fixed in Qt 6, or Plasma integration platform theme does not work to load the default shortcuts map.

Basically, if custom shortcut is practically equal to some standard shortcut, and both are set for the same action (via QAction::setShortcuts(const QList<QKeySequence> &shortcuts)), then Qt won't care to resolve and deduplicate them as one and the same, and instead upon pressing such key sequence would emit "The key sequence […] is ambiguous. […] No action will be triggered." error.

Found it in Zeal (the documentation browser), reported as https://github.com/zealdocs/zeal/issues/1465, but turns out it's a Qt bug.

I have a minimal reproducible example, a scratch project with such QAction.