The traces on the board do tie those pins together. But thats no excuse for poor soldering. While it won't cause a problem i'd still let the retailer know about it.
I think they do that with the machine that puts it together ("pick and place" I believe it's called).
I don't think it's a soldering error, rather a fallback if for some reason that trace gets broken? Or perhaps it comes from the manufacturer like that?
And, after all, mine are bridged as well.