I indeed had to start from a new sketch and redo the entire schematic. Once the data base gets corrupted we don't know of a way to correct it. Even deleting all the lines in all three views isn't enough to fix it. I think the routing code is making some changes that it then doesn't know it should undo again (which is likely a bug) but I'm not really sure. The only known working solution is to start again from scratch.
Peter