In my experience it's quite common to find little nicks like this to the inside rim of narrow stem vases. It most likely occurs when the top is ground flat. If the top was wider then they might give it a bevelled edge to remove the nicks, but I guess there's not much room to do that on these narrow vases. If you think about it, it would be quite difficult for damage to occur there by accident. To the outside rim, sure, but the inside would be quite hard to knock against something.