When building insurance cups, they are built in the warmed interior of the cluster, of necessity. They are there in case of a sudden need to rear a replacement queen. In mid season, they are typically built off the bottom bars of the upper deep. They try to build them in the fringe area of the cluster and outside the existing queen's travel area - not on a full frame of worker brood. They don't want the existing queen interfering in the supecedure process. The outside feed pollen frame is one of their favorite places for insurance cups.
You will see references here on beesource to the the bees building cups and tearing them down on a regular basis. If the cups are built at the broodnest fringe area, the broodnest location only has to shift a little to make the cup location less desirable. Take it down and start a new one over a notch.