Night Watch (novel)/Headscratchers

• Why do Colon, Nobby, and Dibbler remember the altered timeline at the start of the book, before the storm? Alright, so it's perfectly possible that the original Keel promoted Colon and bought a pie from Dibbler, but the spoon has to have been Vimes. Keel wouldn't have recognised Nobby, and given that he apparently didn't attract Madam's attention and wouldn't have made instant enemies of Coates and Quirke the way Vimes did, Nobby probably wouldn't have been following him in the first place.