3 years ago I worked over a root sucker from a crab that had perished several year prior.
2 scion of wine kist, and two of grimes golden.
Year one all grafts took well and grew out.
Year two the winekist started well, but then had major wilting and collapse of foliage. New foliage regrew, but no further extension. Grimes was going along normally, perhaps a bit weak.
At the time I thought some pest or disease I was not identifying might be culpable.
The foliage of the winekist is different to begin with, tomatose (slightly fuzzy) and dark green red.....much like the crab/rootstock it's on (both also have red wood)....so I just let it ride thinking there might be a higher susceptibility to the mystery problem.
This year same thing. Decent bud emergence on both, but then the winekist tanks...wilting, deformed leaves die back....with some secondary growth that seems to be hanging on. Grimes perfectly normal, even set some fruit.

Classic rejection? I can't think of much else to fit, but have never seen it before. I am getting ready just cut out the winekist, a bit of shame as I was looking forward to a red flesh, but there is always next year to try grafting in again with fresh scion on another tree.

Scott