Just a few weeks ago we released a feature where one of the most prominent buttons had a misaligned icon. The feature was reviewed by the QA engineers, the product owner reviewed it etc. I was the first person to notice it. After I pointed it out, everyone started seeing it, too. However, I had to specifically mention that there is a misaligned icon on a certain button. People couldn't see what's wrong even when carefully looking at the button, if you just said "something's wrong with the button". I had to actually say "the icon is not centered correctly". Only then they started seeing it. I guess most people just don't care.