This is a tough one ... I thought I'd find some stressful technique in your diary that would have stressed her out too much at some point but there isn't one... So looking at the plants close-up, I'm reminded of how my Bruce Banners both started flowering... they just didn't LOOK like they were in flower - not the "normal" looking flower at least... and yours look very similar. Mine also waited until week 7 or 8 to "do their thing" - so I guess I'm going to tell you not to worry. I think they've actually gone into flower but not in the "normal" looking way. Give them another week or so... you might be surprised.
I don't see any nute information in your diary but I'm hoping you're giving them something? From the looks of them, I would tell you to add some calmag (once a week only!) and a PK boost (I like General Hydroponics KoolBloom liquid) ... the KoolBloom will also give your plants a bit of a push into "normal-looking" flower...
Good luck!