I plan to use copper for my cherries this year to prevent fungal infection. Last year I used immunox multi-purpose fungicide and it did a really good job of preventing any new infection after I sprayed my cherries but my knowledge with fungicides ends here 
. Not sure what you are looking at here is a fungal disease ether. To me it does look like some type of burn. Regarding the short internode spacing, looking down at the entire branch the spacing seems fine. It looks like something just recently affected the trees since the spacing only on the tips seems to be messed up.
And when did symptoms start? If it’s fertilizer burn, you would start seeing effects pretty soon after the application.
A deep watering would help to remove any remaining excess nitrogen. Then hoping that damaged roots will recover with time.
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