Some films are only available for sale at first.
I can't say about this one, but I have checked others before and they are usually only for sale on any streaming service.
Will be for recent eventually.
I've browsed to Star Trek Beyond in order to rent, where it says, Rent/Buy, but when you click through there's only the option to buy (?). Is there a glitch? Been like this for weeks now.
This is a common occurance, the movie is availble for purchase BEFORE it comes out on Blu Ray but you will not be able to rent it until it is released on Blu Ray on November 1st.
It's not a glitch, it's the way it works, you can buy the movies before thier release date but they are NOT available for rental until thier release date.