Light burn

Nope, it's not light burn... that would be on the topmost leaves and wouldn't restrict itself to the tips. You've got the start of some nute burn... I would cut back on your grow nutes (nitrogen usually does this and grow nutes are heaviest in nitrogen). You won't get any improvement in the leaves that are currently affected but the new growth shouldn't show this problem. Good luck!

After going through the pics in your diary and if this is the same plant. It looks fine. I can't see anything but a nice healthy plant. As for the pic u put up. To hard to tell. But looking through your diary and if temps are 29c you really shouldn't have issues outside. Just cause that's the air temp doesn't mean it's the leaf (canopy temp) cool air blows over your plant so expect your leafs to be a few degrees less. Good luck.

Ah got a picture now, Its possible that it could be light burn from watering the plant during the day with the sun out. Picture is a little blurry. Your growing auto's and your nutrients are a bit strong. I would guess to many nutrients. PH water for a few waters and drop nutrients to 2ml/L