OK...
Well, in my opinion you're doing something that you're plant doesn't like.
Environment (temp, light, humidity) - seems to be good.
Water - using RO water, no problem here. Doesn't look like over/under watering or a water temp problem to me.
PH - maybe a little high, but should be OK if it's not fluxuating drastically.
PPM - seems reasonable.
So if all of your environmental factors are good, it's probably something you're adding to your reservoir in my opinion. I personally think you're over-nuting one of your elements, which may lockout another one. And I still think it's a problem in the Mg area (maybe too much Mg which can lockout Mn which can display similar symtoms to an Mg deficiency).
You should get PLENTY of Mg from your FloraGrow and FloraBloom. I'm not familiar with ViaMag (and couldn't find anything on the internet) but I don't think it's necessary to add any Mg with the GH products.
Regardless, I would find out what I was adding to the res that's causing the problem. This is what I would do:
1. Flush with water to dissolve any built-up salts.
and either:
2. Start with the base nutrients until your plant recovers (which it should) then add the supplements one at a time over a period of time.
or
2. Eliminate one of the supplements per res change until the problem goes away (I'd start with the ViaMag).
Again, I'm no expert, this is based on my own experience, research, and logic, so take it for what it's worth...