I opened my "mutt" hive, and for the first time ever, I found the bees making comb cross-ways between the frames in columns. There are two things unusual about this hive. First, it was from a split I did (my first) last year. I had a frame from each of my 3 hives that had swarm cells on them, and an expert friend recommended instead of cutting the swarm cells out, place the frame they were on in a nuc, and do a split. I placed all 3 in the single nuc I had, and let them fight it out. The other thing is that I didn't have a second deep to add before winter, so I used a medium honey super that had drawn out comb for them to fill with stores for the winter. This spring the hive is going great, so I added another deep below the honey super with Pierco plastic frames. I also added a queen excluder between the brood boxes and the honey super to keep the queen from laying any more brood in there. Why aren't they building comb the right way? What did I do wrong, and how do I correct it?