Greetings, Since upgrading to TB38.4 with Lightning 4.0.4.1, I can't send an acceptance notification when I receive a calendar invite. I receive a message either saying: "Event already processed" or "Error code 8000405" I've tried Synology's CalDAV server as well as Fruux's CalDAV server. I've attached one of the errors that appear in the console along with the code that the error is pointing to. I've tried this on two different computers and both have the same issue. I've tried unsubscribing from the calendar, uninstalling Lightning, using different CalDAV servers and I still have the issue. Any suggestions would be greatly appreciated. Thanks.