What is going on with this runtz plant?

It will happen sometimes after a topping. The lower growth will take off faster than normal. It may twist and do some funky things.

yeah your 100w lights over a 3x2 footprint at 30cm from the canopy is just fine. if anything you’ll be underpowered in flowering. but for now there is nothing wrong with the lights and the light intensity. but you are overfeeding them.

I wouldn't worry about the misshapen leaf - that's kind of a non-issue. Your nute mix looks good but things are "bunching up" with your plant and I think you've got your lights far too close to it. Move the light so it's at least 18" from the plant and I think you'll start to see her lengthen out and look "normal" ... Good luck!