Greetings -
I was very excited to see a film on the AOS site about this subject, as I have this problem with both Den. palpebrae and Enc. garcinia. This link may/may not work for the film:
AOS | Leaftip Dieback
Anyway, short story long, the narrator points out that this is caused by a problem with nutrition, but gives no clue as to what nutrients are present or absent that might cause this unsightly and slightly unnerving problem.
Clues? I'd certainly like to fix it before any new foliage is affected!
Thanks - Nancy