It's a pigment mutation thats all pal.
1 of my cin jacks had it through her whole growth stage, its gone now after coming into pre flower and leaving it.
It's absolutely nothing pal.
growdiaries.com/diaries/148570-grow-journal-by-gottagrowsometime/week/843563
Weeks 3-4 you'll see it. Nearly sure I have a close up of it. Just a muto.
Good luck pal
As far as I can tell, one funny blade on one leaf........hardly anything to worry about.
No plant will ever have 100% perfect leeaves, 100% of the time.
I can't see any real issues to be worried about.