I've had my blackjack plant in flower for about 2 weeks and I'm starting to get new leaves with only 3 points and some newer ones only have one. Is this revegging and how will it effect the buds
If you're on 12/12, it can't be re-vegging (unless you've got major light leaks). You're currently in the stretch period, so some new growth isn't out of the ordinary.
Perhaps you could provide some pictures that we can review? With the grow lights off, preferably.
Here are some pictures of the 1 and 3 point leaves around the new growth and bud sights. I also had an issue with nitrogen burn about a week or 2 back but its recovered now, could the extra stress have done this?