So we only get to see Canute once in 1017(pictured below) and we don't really see his chin nor what he looked like in 1016 so I'm just going to believe he lost the beard in 1016 and 1017 and let his hair grow out a bit before he went full beard and short haircut in 1018.
Canute sailing to Denmark for the first time in years in front of an open trunk with his old helmet from 1013 in it really makes you think. Has he opened the trunk to reminisce before reading and falling asleep on the voyage? Is Thorfinn's old knife in there?