Sort of normal.
Have you looked at camber yet?
Most studs have a bend to them. Make sure that the camber is on the same side as you line them up, or the wall board will wave back and forth.
I am framing my basement. I bought some 2x4s and I also kept some 2x4s from the old finished basement. I just found the actual width of the them are different. There are about 3 different measurements. The differences are about 1/8 to 1/16. Should I avoid mixing them?