Sounds like a hermie.
Seriously, use a long probe to punch some air holes. Roots need to breathe, and rained-down clay soil can have a smothering action. cn
I've aerated with long skinny tines. All of them not just the one. Also went ahead and gave all them a treatment of epsom salt and water at 1 teaspoon/gallon.
I notice that problem is only present on 2 branches/tops. Is there any reason to really worry or do anything about the issue any further?
I don't have the money for any PH tester, plus I couldn't find any way that clearly said how to test soil PH other than a lab so I doubt I'll be able to determine that possibility.
They have developed a bad/worsening case of the red petioles since budding began, despite getting plenty of fertilizer. (N included) Been reading that may be normal for certain varieties. Is that anything major to be concerned with?
All have minimal yellowing of lower sun leaves, growing and (I think) looking pretty good overall etc so I would hate to OD them with too much "care" this late in the game.
This forum may be causing me some plant care related obsessive issues. Harvest is the only cure. LOL