Spyder7answered grow question 5 years ago Week 2 is early for a nutrient deficiency unless the ph is off. When leaves are too close to the light, they react within about an hour by cupping the leaf edges, and if left unchecked (and if you're using an LED) you'll begin getting bleached leaves that are pretty distinctive.
Some nutrient deficiencies can look like nute burn early on. Check your runoff ph. If that's off, flush and correct your ph. If you aren't getting leaf cupping and bleaching (assuming and led grow light), your light isn't too close.
The symptoms look like a magnesium deficiency, but if its showing up in week 2, I'd check and correct ph before adding Cal Mag. After doing that, then add a little bit of cal mag (1/2 strength). If it is a Mg deficiency and that fixes it, it won't undo any damaged leaves but you won't see it spread further or worsen. Some people do add a bit of Cal Mag early in every grow, but this early you shouldn't need it with good soil, so I'd check runoff ph.