Yellow tips and a sticky brown spot

[RubySlippers]

Hi! Anyone have any idea what's going on here? It started with just a touch of yellowing on one younger leaf. Now there's a few more. This morning I found this brown spot on a more developed leaf. It's a little sticky or resiny. The plant is almost 3 weeks old and I haven't given any nutes yet. It's been under 600w MH 24/7. The other plants in the tent are fine. It was recently transplanted and I got a new oscillating tower that could be a bit too aggressive. Thanks for any ideas!

 

[Bikerstonrr]

You also have some spotting on the leaf to the left of the big brown spot. If I had to guess it looks like ph issues. Check this page of the site http://www.growweedeasy.com/cannabis-symptoms-pictures

 

[RubySlippers]

I had thought that could be it, but none of the other plants seem effected. Definitely worth checking out, though. Thanks!

 

[RubySlippers]

Sorry, just realized I didn't post this in the right forum! Oops!

 

[Bikerstonrr]

Check it out. I once had a plant that showed nitrogen toxicity while her sisters (same feeding schedule and nutes) were fine.