The same is true at every other example where a dual carriageway ends and becomes a single carriageway. Each carriageway of the dual carriageway is represented as a line following the centre line of that carriageway - the single carriageway is represented as a line following the centre line of that. This  necessarily involves bending the ends of each of the duel carriageways to meet the end of the single carriageway. This is just an example of exactly that. 

