It's poor finishing but if the areas we can see in the photo are the only ones with excess solder then it shouldn't cause you any issues. It's mostly on parts of the ground plane and doesn't seem to be bridging any pins. The board will surely have been powered on already during factory tests.
For what it's worth mine looks totally clean on the underside so you could probably return it based on poor quality control if it worries you.
For what it's worth mine looks totally clean on the underside so you could probably return it based on poor quality control if it worries you.