Weird leaf

I cut off 2 out of 3 of the leaves that looked like this, and my question is what do think it could be?

a feeding issue?

Maybe magnesium deficient, time to review the menu.

If it's deficient in something pulling the leaves off is only gonna make it progress to the next set of healthy leaves.

I got a flowering nutrient with an npk ratio of 1-2-2. The bottle says a serving is 7 mLs, so how much of this and how often should I use it?