Bubbles (& I'm assuming they're in the sidewall) are nearly always caused by one or two things: either incomplete bonding of the layers during manufacture or by hitting lotsa potholes. Usually defects in manufacturing show up fairly quickly, under a year or so.
So, no, it's not normal.
And, yes, they're dangerous simply because they have a tendency to blowout.
Personally, I'm a big fan of the Goodyear F1 A/S though they have a tendency to get noisy when they wear.