So it’s looks like the hive pillow is doing its job. Moisture is rising up through the inner cover hole, passing through the wood chips, condensing on the cold top cover, dripping down on the top of the pillow, where it then evaporates through the holes in the ventilation rim. Hence, the bees inside are kept dry.
The only thing I’m not thrilled about, but I’m never thrilled about it and it may not have anything to do with the hive pillow, is that the bees are clustered right up against the inner cover in a giant ball. Are the bees following the heat that’s escaping through the inner cover hole? Are they simply covering the sugar brick I recently added because they’re low on honey? Or are they just naturally clustering in the warmest part of the hive?
You’d think they’re just following the heat, and that the answer to all those questions is yes, but I have other colonies where the clusters are in the bottom of the hive, and they’re not following the heat up to the top of the hive. In any case, I don’t think the pillow is harming the bees. So that’s good enough for now.