Is this normal for a seedling?

double check pH... what is listed in diary is fine. I'd definitely wait and see a bit more before any specific decision on it. May just grow out of it... more oddities seen with those first 2-3 growth nodes than later on. first couple weeks the seed power everything, but if you stick to a 1.3-1.5ec (650-750ppm) nute mix, you can start to fertilize and not worry about burning a young plant. if it is a picky plant, easy enough to observe and skip fertilization next irrigation. already a fairly low ec, so it wouldn't take much. fertilize every irrigation with 10-15% runoff waste at this point, and you'll maintain a fertile substrate and consistent pH. If you calculate ppm of elements, makes diagnosing things easy. check out a table in virtually any of my diaries for a ballpark of each... NPK are rock solid, but the Ca, Mg and S value depend on your tap water in some part. i have hard water, so you may need more than me with these. just a ballpark idea around 6pH.