Apple drop Enterprise, Winecrisp, and Ashmead's Kernel

I am seeing apple drop on my apples- Enterprise, Winecrisp, and Ashmead’s Kernel. All of the apples are bagged. The couple Ashmead’s dropped were small but looked ok. Winecrisp are decent sized on the drops and I had only a few drops. The Enterprise drops are big apples and I have lost about a half dozen. All of the apples look really good, free of insect and bird damage. No rots or Summer fungus are present. It has been a bit dry but not excessively so. The grass is still green. Leaves on the trees still look good too. Any ideas?

Last year I lost maybe 1 or 2 Enterprise to drops. The rest really wanted to hang on the tree just like PRI literature claimed they would as I detailed in the post below.