Looking, A1Sas is currently, temporarily, a single carriageway motorway. It remains signed (both ways) as A1Sas.
The A1 has, temporarily, taken over one the carriageways of this and the SS64var (which has a lot of second carriageway sitting in situ) so it can rebuild the mainline.
I've moved the A1/SS64Var junction to the roundabout, and reshaped both A1 bits to better fit reality