AUTOFLOWER BROWN SPOTS HELP!

As the others say, check if your pH is low (like <5.9 or so), coz that can cause lockout of some nutrients. If it is, first thing I'd recommend is some calcium and maybe a bit of magnesium to buffer it a bit. Doubt your pH would be too high.

You haven't messed it up; it's likely a pH imbalance, and it's something that happens to all of us. If you're growing hydroponically, it's essential to have a reliable pH meter. As mentioned below, I also think there might be a pH fluctuation in the growing medium. But don't worry, if that's the case, it's just a matter of adjusting to the right parameters. Any range between 5.8 and 6.5 is "acceptable," but I personally recommend 6.1.

Are you sure the plant isn't set into the media too deep? Recently I had low PH and a plant too deep...looks real familiar.

You didnt mess up at all this is a typical sign of a ph flucuation I would get your ph pen out and double check that ph it should be around 5.8 to 6.2 she doesnt need much at this stage so im prettty sure its not a deficiency. I think high humidity can cause some leaves to warp but this udually clears up in a day or so or with fresh new growth. I would also check your water tempetures if they are above 22c that can cause some adverse effect on your plants these symptoms are common for high tempeture water been growing dwc for about 5 years not many problems I havent come across lol if all that is good I would flush her and then re introduce a lower feed :) though its upto you shes has alot of green growth on her she will be fine maybe not the fastest but she will grow. Best of luck and keep up the great work :)