Unfortunately, as with everything I guess, it's probably only a matter of time. I am hesitant even to point it out to the building management - but they also have tree health folks stop by once a year - so I'm going to go on the assumption that they are aware of the problem, assessed it, and decided the tree has a number of years left.

Or they didn't see it, which is plausible because they come in the summer and this appeared in fall. Anyway, I refuse to be the bell tolling for this one. Too attached :)