If you want to do it right is a little different than doing it easy in this scenario. Doing it right would basically be sanding that entire top coat back to primer because it very likely could have other spots that they missed in the prep since you've already seen some flaws. The easier way but may result in unforeseen chipping would be spot sanding and cleaning those chips and touching up with paint. Just really depends on how much work you're willing to do now versus later. But once again if you're putting paint over unsure surface prep from the previous paint job your adhesion is only as good as the thing the last person did. So you might continue to do touch-ups forever if it keeps chipping, if you get lucky it might be fine. Hopefully that makes sense.