This has been my experience as well, viewed from both sides.
Additionally, sometimes code reviews for newcomers is more involved because we want to see how the person reasons about the problem. It's also helpful to get astonishment reports from newcomers during code reviews.
One thing I always beg for at the beginning of a tenure is for scathing code reviews. Tell me everything your heart desires, if you have the time. The more we get of the way early, the less we need to worry when our minds are in sync.
Additionally, sometimes code reviews for newcomers is more involved because we want to see how the person reasons about the problem. It's also helpful to get astonishment reports from newcomers during code reviews.