Seedling discoloration

Hi there and thanks for reading. I've got a gorilla cookies autoflower that I started off in a solo cup using seedling starting soil just to give it a start and get healthy enough and big enough so that it wouldn't get burnt or anything like that. After a couple of weeks I transplanted it into a 3 gallon pot with ocean forest soil. For the last few days I've noticed there's slight discoloration on the leaves. It's about 3 weeks old. I'm 100% sure I haven't overwatered it and haven't underwatered it either. My best guess is that perhaps the ocean forest was a little too hot and once the roots made it past the seedling starter soil, the roots got slightly burnt a little bit. Has anybody else had similar looking seedlings and if so what would be the best possible explanation for the slight discoloration. Aside from that it looks fine. Thanks

i’m also new and my understanding from experts is that yes it’s a bit hot for young plants but they will acclimate if you keep everything fairly consistent. experts correct me if i’m wrong lol

Like a kid with a big sweater, she'll grow into it.