I'm pretty sure this is Sky intentionally blocking advert fast forwarding. Perhaps a small scale trial.
I'm watching Revolution recorded from a couple of weeks ago. As the adverts start I hit fast forward.
Twice now it's flicked itself back to play as it comes across an advert for fabreeze. It did this both in fast forward and fast rewind. And indeed during the ad fast anything was instantly cancelled.
If this is as above (and I can't explain why not), "it's started". It's a reality.
Not good.