I have a sour diesel plant that did the same thing. Exactly. The leaves would start out looking really weird, and grew into these hourglass shapes. Like the middle of the leaf is really really skinny, making it look like bugs are eating at he sides. The plant eventually started growing normal leaves and the deformed leaves are at the bottom. With my plant, my only guesses were that it is a sign of some nute burn or a seed/pheno characteristic.
But yes. I had the same issue and my plant is healthy, healthy, healthy...