Lots of stem plants do this when something isnt right. The main top stunts, stops growing and then side shoots form. It's like the plant says eff it and decides to start over.
I believe you have a fert issue, although Im not sure what it is exactly. Just going by the pics the plant looks low on Fe, it's pale with no red or pink color a all. My aromatica does this for two reasons, too much csmb, or not enough Fe.
Looks like you are dosing csmb at roughly .1 ppm Fe. That is a reasonable amount, it's too much for some people (like me) but less than a lot of people dose.
Personally I would cut that in half and add an additional form of Fe to make up the difference, or even raise it a little. No idea if this would work, it's just what I'd probably try first.
Either that or leave csmb like it is and dose additional Fe on top of it, another .05 ppm or so to begin with, or maybe .1
Or the simplest thing to try is bump csmb up a little, something like .12 or .15 ppm and see what happens. Things will either get better or worse. Go from there.
Also saw your thread on persistent BBA. To me that sounds like the tank is getting too much micros, but it could also be a number of other things.
Every tank has a sweet spot where the proverbial "light comes on." Plants perk up, the water gets clearer, and nuisance algae goes away. It's there, you just have to find it.