Just keep up with the 18/6 and they will veg. The smooth edged leaves show someone has played with the light cycle. If you have kept them at 18/6 then they had to have been cut from a plant going into flower to develop those sort of leaves. Nothing to worry about though, as they are already producing new serrated edged leaves... they'll veg eventually.

Bit rough coming from a clinic, did the "light sensitive" stuff come from the clinic too? Sounds like they sell a lot of bullshit and spin along with their clones.