I watch some British crime/mystery type shows on Roku on my Fire Stick and use captions all the time. One particular show (Vincent) won't display captions when I try to watch it on the Fire Stick, even though CC is turned on and works fine with other shows. I concluded that Roku just didn't actually have the CC for that show. But I later noticed that the show Vincent does in fact have working captions available when I watch it on Roku's website. Wondering if there's any way to get them to work on the Fire Stick?