I have tons of lessons saved as Favorites. I just sampled the first ten, i.e., the first page of the more than ten pages saved. Each of those ten lessons, some of the videos more than ten years old, some quite recent, loaded promptly and played as they should (today, 6pm Mountain time).

I have a rather moribund DSL access to the web, compared to all you folks who live in the big cities with big lights. My system is W10, Edge browser.