I'm doing this backwards... No rh or temp meter in the cupboard as I use a ecotech controller for that and it's not worth setting up in a temporary cupboard.
Soooo..... This could be rh issues, calcium off the top of my head or possibly poor air exhanfe as there wasnt extraction on the cupboard till last week.
I've been over every leaf with a macro lens and no creepy crawlies. So I figured I'd ask for any eagle eyed growers or those who have seen this type of leaf damage/mutation opinions as I've not seen it before.