The only explanation that I can muster up for what you are saying is that the plants are an auto flowering strain.

Can you please confirm:

Were there any signs of flowering/budding before you switched to 12/12?
If so, it is definitely an auto-flower strain and you should therefore keep it at 18/6 or with even more lights on time.

You compared the buds you have to that pic you found on the net of a big fat juicy bud.
This I would safely say is impossible for a non auto-flower strain that has only been on 12/12 for 2 weeks.

This might also explain why your plants haven't had a stretch of any description since you switched from veg.