Heat Stress? Or?

My plant has done this twice in the past week, it seems to get very weak the the top starts to fall to one side, the stem and branches seem to loose their strenth to hold themselves up, is this heat stress?My temps stay between 73-78 degrees and i'm only running a 4 4' T5, 12/12 light schedule. Thanks again.

picks would help but doesnt sounds like heat stress

Here it is, the stem and branches are very soft and weak, not near as rigid and strong as they usually are, the picture doesn't do the leaning justice, water shortage? but the soil is damp half inch down.....

You got a fan in there to give it some strength

I have a fan on it 3 hours a day. It normally stands straight up and is very strong, last time it did it i raised the light and lightly watered and it perked up in a few hours, its like its wilting, normally my lower branches with fan leaves are almost straight out and not drooping

Not heat stress.
Get a fan on during the whole 12 hrs if poss. And let the soil dry up a bit sum strains arent as thirsty as other.
I had N.L indoors and i was watering when needed. Amd i put N.L outdoor and i waterd once and forgot this whole week just been busy. And thinkin its gonna be all yellow and fallin over i go see and it lools better then my indoor.