Are the effected plants by chance ones that were FIMed? If there's any ruff housing with the new growth bud (FIM comes to mind ) it can damage forming leaves causing abnormality's like that. I've had leaves that were missing chunks grow in, some of the leaves on my White Widow SCROG wound up curled off to the side because half the leaf was stunted by being pressed against the wire while it was forming.

Keep an eye on em for sure, :weedpoke: but they look pretty happy over all :hippy: