Hello all! This happened to me too, where they appear to be dead so i came online to do a quick search. I also have a very full and bustling hive and they have plenty of food stores in their super so they must be sleeping/resting between finishing the cells. already starting to put nectar in the flow frames! very exciting! As you continue to use your flow frames, do you find they can seal them faster after the first use and begin to refill them?
Welcome Liz! What a perfect last name to be a beekeeper 
Yes, once the bees have waxed up all the cells for the first time, the next rounds go much faster. All that extra work of extending the cell ‘tops’ to make them level and cappable is done and all they have to do from there is reclose the seams. Plus, with all that prior waxing and nectar storage the idea is more obvious to the beeswax they get right to it!
Edit: more obvious to the BEES and they get right to it. Silly autocorrect 