It looks like an Amazon issue.That screencap shows included with prime. Just close the More Purchase options box.
Whatever it is it's not an AnyStream issue.My episode 3 is the same as your episode 2, and episode 3 onward, for your screenshot, are dated Jan 1, 2015.
My screenshot shows all of them dated Jan 1 2015.
As was said, probably a licensing issue.
Happens often with various aspects of some shows, some seasons are blocked to me because of the musical tracks in those episodes, they are not licensed in Canada, but they are ok in the US.
It is what it is.
I can not play the last four episodes in a browser but I did find the same series on Tubi.I can only see a button at the top of the list, where you always have the stuff to rent or buy things. First, there is the channel, and then they tell me to rent or buy the episode/season. However, as I said I have no clue if that includes all episodes or just the four.
https://tubitv.com/series/300002584/secrets-of-the-universe