Diseased plant? (Brown patches, crinkled leaves)

So my plants got a bit older, I had this issue on the very first leaves and they seem to be moving up to newer ones. I've scoured all the image charts and tried to find a cause to the problem, can't really find any causes that match the symptoms.

I've added cal/mag in case its a calcium deficiency. The grow environment is quite hot but doesn't go over 30 Celsius, ph is around 6.3 and I'm using canna nutrients at about 1/4 the recommended dose as my plants are auto flowers.

Any advice would be appreciated, would like to save my baby

Looks like cal deficiency. Your instinct was hopefully right.