Missing Episodes (Multiple shows via On Demand)

I'm brand new to Directv (Premier) having just switched from UVerse after many years. Question: When I look for shows via On Demand, A LOT OF EPISODES are missing. Example: Yellowstone (a Paramount + show that's included in channels) has only six episodes from Season 1 and six from Season 5. Where are the rest? Also, an HBO MAX series (also part of my package) called "And Just Like That" has only the first episode marked "trial"? What is going on? I'm confused and can't find a direct explanation so far other than "it's the provider"?