I imagine it varies by publisher, but I was just working with a student who uses the textbook Big Ideas Math Accelerated: A Common Core Curriculum by Larson and Boswell, and I found an error within minutes of looking at the book. What do I do with this information? (It's entirely possible the correct answer is: just live with it.)
Treat it like any other book you find a mistake in: send a letter or email to the author by way of the publisher. I would wait until the end of the term and send all the feedback in at one time, then.