I think the mystery is solved. I checked my light timer and there was a switch on "outlet on" that should have been "time on." So I've been giving them six weeks to a month of 24/24! That will change today. These three plants are "Lemon Lotus" from Bodhi. Said to be a Lemon G and Snow Lotus cross, otherwise known as a Lemon Thai and a Hawaiian (two Sativas). They grew like any other plants until they were a foot high. They then became incredibly bushy, dense plants, and they were somewhat different (from each other) in structure and color. All have great lemony aroma. They were trimmed back and flipped just before Christmas, but two weeks later I accidently set 24/24 ] and they have been growing under bright LEDs ever since. The grow room is too cold (55F) but there's not much I can do about it this time of year where I live. So the stress of the cold, and the influence of constant light, has produced this. Maybe I can flip them back to a flowering mode, and the final buds will have something unique from all the stresses.
Or not. Thanks for all the input. The diagnosis was correctly veg, and I found the cause with the first thing I checked. Can't wait to see how it all ends...