Ah...that's life. I had a volunteer runner that had gone like 18 inches under the ground from my cascade crown and popped up there, so I hacked it off and transplanted it down to another line. It looked sad and mopey despite all the water it was getting...now, about a month later is has 3 or 4 brand new bines. I won't get anything from it this year, but it's a free rhizome!
Back to your subject, I wouldn't worry about the growth tip. I have had that happen before, and almost inevitably, it busts out a new growth tip from one of the crooks where the leaves are, a bit further back from the end of the bine.
What I can't figure out is why my 3rd year mount hood is only like 6 feet tall, when the 3rd-year cascades and crystal plants are up to the top of the line and very vigorous. And the damn EKG won't grow for sh*t either. It's a 2nd year plant, and the thing is barely 3" out of the ground. I might have to replace it with another crystal.