Fan leaf

Nothing to do with water, it is just "one of those things" and nothing to worry about. Remember too.......no plant will ever have 100% perfect leaves, 100% of the time!

because it is half the leaf, i'm gonna say "variegation" which is a harmless mutation.. New growth displaying chlorosis can be from too much K or P, too. But that looks too systematic on the top half of newest leaf.. a clear green half and a paler half even split on middle finger (ha). but then it does look like some chlorosis is occurring, but again, reealy hard to assess color with what seems to be a blurple light, and any grow light for that matter.

Just a common issue that your plant will grow out off Pigment mutation I've had it it on many grows. Good

Thats really bizarre to see a leaf with 1 side yellow and 1 side green on the same blade. Thats pretty unusual, and i can't say i've never experienced that before.. So i really can't give you an experience based answer to that. I'm sorry. Over all the rest of the plant looks great!