https://store.steampowered.com/app/1622900/Star_Trek_Infinite/

I have the same problem with the Paramount+ app on my LG TV. If the commercials that run before the episode are widescreen, it will stretch the episode from the original aspect ratio. Letting the episode play for about a minute, then exiting to the menu and resuming playback seems to pop it back to 4:3 for me.