Allfoliagenofruit

Something you might want to consider with the lights if you haven't already is the distance of the lights to the leaves. With my minimal experience growing other plants like tomatoes with lights, having the light far from the plant would make them leggy with long stems which seemed to be confirmed with what I read online. If the lights are already close to the leaves it may be what's resulting in that leaf growth without height growth since additional height is not necessary to reach the light.


Here's an explanation I found from crop scientist Michael Neff:

A photoreceptor protein called phytochrome B (PhyB) detects red light, far-red light, and the relative amounts of each.

“It’s a great photoreceptor for reading whether you’re under the shade of another or near another plant, because that light that is reflected off your neighbors is enriched in far red,” says Neff. When PhyB senses a greater proportion of far-red light, it signals the plant that it’s in shade. That spurs the plant to grow taller in an effort to get beyond the shade to a sunnier spot.