Okay, so I take it I’m fishing for explanations here. Sounds like it is a fine graft union, then.
These photos of the Dabinett/G222 combo should probably be posted under the categories: Where not to plant your apple tree. And: How not to manage your apple tree. The thing that gets me is that every other tree has been effectively managed the same, and this one is the runt. This tree is an outlier in my yard, to be sure.
My back yard is wet. This tree is in the wettest spot along with the Enterprise/M7 combo. Even Bud.9 is doing better despite its reported dislike of wet soil. I suppose it is struggling against the grass and the wet. Probably a hard battle to win. More mulch will make it wetter.
I am hoping to find time to put in some tile to the storm drain inside my lot. I have a fairly large swampy spot near said storm drain that I’m hoping tile will fix.