We have had no contact about rescheduling but when I logged into the Lufthansa site I see we have been moved to an earlier flight from Glasgow and a later flight to Copenhagen. That gives us about a 10 hour layover in Frankfurt.Yeah mate, return flight is fine.
As @ahalfallover says, it seems like it could just be difficult for large numbers to get over.
I could just about put up with the original flight time from Glasgow if the second leg was delayed, but what’s the point in moving us to an earlier flight if the original one is still running??