Damaged COTYLEDONS

Nothing to worry about. Once they start dying that's your signal it's time to add nutrients. I mention this because it looks like you may be using nutes early? Either way, just pay attention to the cotyledons and once the tips start yellowing or dying, then begin feeding nutes. This will work even if you only have a single cotyledon. The deformity shouldnt really affect your baby much in the end so no worries.