Is this because I'm using the DirecTV / Apple TV app on my Sharp Aquos TV?
Subscribers can access any Apple TV+ episode from any device that supports the Apple TV app. Your equipment is not the reason.
Please try navigating to the main details page for the whole show (i.e. not to a specific episode). That page for the show will list all episodes from all seasons. You can navigate there to any different episode and resume watching from there, thereby updating your personal watch progress point.
To find the main details page for a show, you can
- find the show mentioned anywhere else in the app, outside the Continue Watching/Up Next row, including Search, or
- click-and-hold an episode in the Continue Watching/Up Next row, then choose ‘Go to Show’ from the contextual menu that will pop-up.
Please ignore the MacBook Air tag, I don't watch TV on my MacBook.
As an alternate method, you could use your Mac to watch a few seconds of your wanted episode, if you find that easier, to update the Continue Watching/Up Next queue list, then resume on a different device.