Once you've done the phased zones in Icecrown, as in everyone is on the same (finished) stage, the phased zones don't break follow.

At least, I was losing follow in a lot of places, but once I've opened all of the dailies I want to do, I don't have any phased regions anymore. I've not done all the quests in the zone, so there might be a phased area or two somewhere there.