Welcome Phaze,
Don't worry about the knee-jerk reaction of repotting. There's nothing you can do about it now but try to learn from the mistake.
With the new single bladed mutated leaves I've seen this happen only one time with my own plants. I think it happens when there is a frequent dark period interruption but not long enough to really revert to veg. Make sure that when it is dark, it stay 100% completely dark the whole time. I'm talking about: not enough light to see your hand in front of your face sort of darkness.
If the issue has a nutritional or pH cause then I think that could be resolved by flushing your coco. The PK 13/14 probably wouldn't cause this issue because from what I can remember this is more related to the nitrogen in the plant than the other elements. Nitrogen is crucial for healthy protein and hormone manufacture. Canna Coco A+B carry more nitrogen than any other element and if you had been running just A+B and Rhizotonic during that long period you could have been over feeding without enough run off.
A quick way for you to know if it is a nitrogen issue is to remember back to early flowering, the first week or so. Was the plant VERY dark green, almost to the point of being this blue/black/green sort of shade? That was probably an imbalance of N to PK that started a while ago which you are now just seeing the effect of.
You can take the best course of action as you have the most information in your garden. If it is a lighting issue, and you know it, then take care of that. If you think it is nutritional or pH then you can run 3 gallons of pure water per gallon of coco through the planter, drain it clean, and then feed again with this mixture:
1.25ml/liter, 5ml/gallon Canna Coco A
1.25ml/liter, 5ml/gallon Canna Coco B
0.5ml/liter, 2ml/gallon Canna Rhizotonic
2.25ml/liter, 10ml/gallon Canna Cannazym
3.5ml/liter, 15ml/gallon Canna Boost Accelerator
Depending on the starting EC of your tap water this should take you to around 0.8EC to 1.0 EC with a balance of nutrients in a ratio of 2-3-2 with 2.5 Ca and 0.5Mg. The magnesium is a bit low in the mixture so if you were to add anything you can use a pinch of Epsom Salt to up the Mg and Su levels just a few ppm. Don't over do it.
That would flush the media clean, and start to rebuild your buffer. Stick with that high phosphorus mixture for a while, coco provides enough potassium naturally and you don't need the nitrogen at the moment. Keep an eye on your magnesium and your pH and you should be good to the finish.