Yellow marks on one leaf

Hi guys, it's my first grow and I have no idea what I'm doing! I've read a bunch of troubleshooting guides and haven't found what I'm looking for.

I have some weird yellow marks primarily on one leaf only, I'm curious if anyone knows what caused it?

Also, as you can see, I have some drooping going on, can anyone tell me if this is overwatered or underwatered?

Any other tips would be appreciated too!

(misc details: last watered two days ago, it's an autoflower on 24 hour lighting, planted 2-3 weeks ago, foxfarm ocean soil, a 3 gallon cloth pot, mars hydro 600t about 24 inches from plant, 50% RH, 27c Temp, PH'd distilled water)

This is the second claw I've seen this morning. Too much nitrogen or poor watering and care. Marks on leaf look like the start of calcium deficiency. Let it dry out well between irrigations.