genetics... too much light.. combination of the two.
you can stunt a plant with light. the nodes would probably be tighter than what is seen here. If you did something 17days ago that increased intensity, that could be the cause and the previous growth would look more normal before that point.
I think you have 2-6" left of vertical growth, if only 17 days after flip. someplants simply grow more after flip than others. if you have an inkling of such variance in growth pattern you can train them differently. I train lanky plants about 7-10 days beyond flip and the short bushy ones i let go vertically immediately at flip (scrog in use). Even doing that i often have to HST some taller colas if i have many strains running.
Without a little familiarity, you just run with what happens and do your best with it. Your vege growth is certainly nearing an end but is not 100% done.
If you think it's the light, go raise it 2-4" and see what happens over the next few days... stunting can take time to recover, so if oyu do this, committ to it and wait for an observable reaction. Within 1-3 days depending on severity of potential light stunting, you should see some visible differences in growth pattern... as long as some vege growth does remain. It would be an incredibly fast flowering plant if it's done by FD17. Shouldn't taper off till 4+ weeks. Definitely slows before 28-30d, but continues for a while. Longer flowering plants will exhibit vege growth deeper into flower phase.
vege growth = growing leaves and stem elongation. even though it's in flower when you give a "long night," hormonally speaking, it is a transition as far as resulting growth.