All plants can grow to the roof and burn. All plants can do things we don’t predict. All plants can get sick and stay short. Autos are just that. Unpredictable. So is the whole journey inside a Grobo.
I have one that is short but it has the most dense buds ever. Dripping wet with trichs.
I have another that is a textbook Grobo grow. Right height, right canopy, and buds growing sticky just fine.
Each will provide 2 to 3 Oz once harvested. Only took 120 days. I do not see the problem.