Laminate flooring may look like natural wood, but it isn't. The wood pattern is merely a very thin photographic layer covering a high-density fiberboard (HDF) core. The "photo layer" or "pattern layer" is coated with a hard clear protective coating, but if the coating gets scratched or otherwise damaged, moisture can reach the core of fiberboard, which swells when exposed to moisture. This means you can't sand out the defects as you would if the floor were hardwood and the hardwood floor were bubbling, nor can you scrape the edges or do anything else you'd do to solid wood.