Too many bees rather than too few would increase the risk of absconding.
But if you don't have a lot of bees in the apidea and the queen takes 3 + weeks to mate there will be very few left and possibly not enough to cover brood when she starts to lay.
The other problem with weak apideas late season is wasps.

The main reason for absconding is (a) overheating, ie Apidea in full sun, (b) mating swarm gone wrong where all the bees leave with the queen on her mating flight and then settle somewhere without returning to the apidea.