Something was wrong. They all go threw a stretch period and then the flowers fill out. One must realize that the plant will be growing for 2 months or more. Its goin to grow.
It is true they all go through a stretch period but not all plants stretch as much as others and different factors depend on this. Just because his only stretched 3" does not mean something was wrong. Here is something that should answer your question whswakboard
During the strict 12/12 cycle, a female plant will fill out more. More leaves, more branches and more flowers develop until eventually, plants reach a peak period of flowering. Your plant will start to almost take the shape of a Christmas tree. The lower fan leaves will be stretched to the maximum in order to receive the most light. Running upward in a cone shape, the plant will exhibit strong floral and leaf development.