We have observed wasps go into a second procreative cycle which is quite unusual and we've only (so far) observed this behaviour prior to harsh winters. Probably only coincidence but there you go.
The pattern with a second procreative cycle is that wasp colonies produce their sexual gynes pretty much on queue around the end of July and the resident queen then stops laying brood. The workers switch to sweet feeding as with no brood they are unable to get carbohydrates from within the nest from larval digestion of chitin from insect skeletons. The sweet feeding continues for a few weeks and then abruptly stops giving the false impression that wasps have disappeared. In fact, the queen has laid a second round of sexual gynes that need insect prey for development so the workers switch back to hunting (protein feeding).
Once the new sexual gynes have been produced the workers switch back to sweet feeding late on as they have done now. This repeat procreative cycle does tend to catch beeks out a bit because they assume the wasp problem has gone whereas it's more akin to being in the eye of the storm.
The real problem here is that if the bees have started to cluster they won't necessarily defend their stores leaving wasps free entry to rob out winter stores. There's no sign of fighting. Just head down starved bees in late winter or early spring. Now is a time for close monitoring and if the bees are clustering then even tunnel entrances won't necessarily be enough to prevent robbing.
