No...probably not...sometimes leaves just yellow...do all the other leaves look good, except for the ones that are yellow? How old is the plant...is it vegging, or flowering, uner what lights with what soil? Leaves can yellow for numerous reasons: not enough food, too much food, root bound, not enough light, pH is too high, pH is too low, temps are too high, temps are too low, overwatered, underwatered, bad soil can make leaves yellow...so literally anything can make a plant's leaves yellow..