But if you refresh the page, it will retrieve necessary data from backend, so it may have something to do with changing state that does not trigger component to be re-rendered.
Update: This issue will happen after refreshing on professor page and course page will appear to be empty in this case. Apparently, switching tabs will not trigger fetching.
If you go to https://peterportal.org/search/courses and click professor tab on the top left, you will go to https://peterportal.org/search/professors and see an empty page about professors like this, which is not consistent with course page.
But if you refresh the page, it will retrieve necessary data from backend, so it may have something to do with changing state that does not trigger component to be re-rendered.