When your hive is acting strange, is not building up comb, is not feeding on syrup, the main culprit may be a problem with the queen.
In the case of the Mirror Hive, the cluster seemed quiet, there was not a lot of activity at the entrance, and the syrup was left alone. Upon inspection I saw eggs, but the wrong kind!
When a hive goes queenless, and in this case, without any larva from which to create a new queen, the chi of the hive gets out of balance. Sometimes, a worker will meta-morph into what is called a laying worker. She will lay eggs, but the offspring will be all drones, a net drain on the hives resources and the beginning of the end of the colony. the tell-tale sign of a laying worker is more than one egg in each cell, usually two or three.
I had a spare queen that I had ordered from a supplier and added her directly to the hive along with a lot of smoke and syrup spray. I also added a frame of brood and bees from another hive to both increase the size of the colony and give the bees some young larva to stimulate the colony's emotional health.
I'll leave that hive alone for a week and see if I find that queen to see if she survived, or as an alternative a queen larvae under development from the frame we added. We will see!