@Eskimo - this also happens in a SwiftUI app that I've made responsive to AppleScript commands (using NSScriptCommand). Whenever I issue it an AppleScript command it will complain abut UI responsiveness (which isn't wrong per se - as AppleScript is running on the main thread, but is there any other option?)

This also seems to happen when making a SwiftUI application scriptable (integrating AppleScript responders like NSScriptCommand) This does not happen directly when starting the app, but only after issuing it an AppleScript command. So I'm not entirely sure if this warning is right. Responding to AppleScript is blocking the main thread, but I don't see if there's another way as it seems to be all Apple internals.