Inconsistent moisture is one potential factor here. Obviously there is no irrigation running over the winter, and precipitation was hit and miss, with a very dry February and wet March. While we often think of something dry as being firmer than when wet (like pasta, for example), that's not always the case. If you've ever gone for a run on the beach, you quickly learn that the firmer sand is the wet sand, closest to the water.
In fact, for tournament preparation, you will often see bunkers being watered by hand to keep the sand firm.
While moisture may be playing a role, we are also revisiting how these new bunkers are being maintained. With many of the new bunkers being smaller than the old ones, we have elected to hand rake them, instead of using a machine. Even on the larger bunkers, where we do use the Sand Pro, the bunker faces are steeper than in the past, and we've been making sure the mechanical rake only stays on the flat portion of the bunker.
So, it's a bit ironic that we are now finding that our bunker maintenance protocol, which is designed to keep the bunkers in the best condition, may actually be contributing to the lack of sand firmness. That is, with no machine in many of the bunkers, there's no on-going compaction. With no machine on the steep faces, again, no compaction. What's the answer?
This is clearly not a one and done job. We will be looking to get back in these bunkers every couple of weeks initially, then back off as we see a change in the sand firmness.