Agreed, too much nitrogen, but the "over watering" won't retard growth, but using old soil definitely will.
Old seeds can lead to poor germination, but not retarded growth.
Which leaves the obvious cause - poor genetics and this seems to be quite a regular occurrence with this breeder and was the cause of me swearing off autos all together.
Next time, grow with 100% new soil and I would suggest going with photoperiod plants. They are far more stable genetically and generally yield much more, all while needing less electricity.
Hope this helps,.......
Organoman.