Light Stress?

I've got a closet grow going in a 2x4 tent. I can keep temps around 85 at the height of the day and its growing under a 250w hps. I've got a Blueberry growing, mostly its been doing fine, but it just hit its 2nd week of flower and all of a sudden I have this issue, only on the newest of leaves. I've got burnt tips twisting up, and the edges of the leaves are yellowing. Is this light stress? I've got an Original Amnesia and a Super
Lemon Haze right next to it that are doing fine.