In 5.21 it says
but should be
In lab 5.22.d the answer should be false.
Thank you, for the input, this will be corrected in the next update.
How often do updates happen?
1-3 times per year, depending on changes. I think one is not far off. We cannot change things one at a time in real time as the entire course has to be swapped out, so we batch changes. That's one reason forums are useful to watch for errata
Thanks for your careful analysis