Traffic squeeze, bad drivers
Off the roundabout, South on Dryburn Road is 2 lanes for ~4 metres before squeezing to one lane for the traffic-light pedestrian crossing and then re-widening to accommodative the Southbound bus lane/stop. If you are a cyclist taking this section then you really should take primary position as soon as traffic allows but many drivers do not accept that and will race up behind you and then alongside you if you have not made it to the bus lane yet.
I'm not sure what is the best solution, perhaps a sign "Give cyclists space" or if it is possible (and safe for crossing pedestrians) to add a drop-kerb before the traffic lights & painted cycle lane so cyclists can use a short stretch of the pavement to get to the bus lane.