This is my first year at bee keeping and I've experienced something that I haven't seen any other messages about. We have 2 hives, one is a Langstroth and one is a top bar. About 3 weeks ago I went in to check them and found the Langstroth doing very well - capped honey and lots of brood. The top bar, on the other hand, was completely cleaned out. There were still bees, but all the honey and brood were gone. It was perfectly, squeaky clean. I bought a new queen and put them on sugar syrup. I went in again yesterday to see how they were doing and found new brood and stores of honey/sugar syrup. BUT, now the Langstroth is cleaned out. In both cases, the hives have had plenty of room for expansion and seemed to be strong hives from my limited perspective. Please advise.