It's quite hard to make out, but the only time we see bubbles exactly like that in my industry is after a poor quality body repair, which is very common on what we see (Caravans and Motorhomes).
I don't know if the van was new when you got it, but it's not impossible for there to of been a repair prior to you receiving it. I don't know about the commercial industry, but in mine, any repairs by the factory are registered against the chassis number, and can be traced back if ever needed.
I'd be having a chat with your supplying dealer if it was me, because they might except responsibility.
In my experience it will only get worse, and the paint tends to disappear on the blisters, leaving it looking terrible.