Interesting how this is still an issue. I am also curious if this is a Roku or Amazon issue, gut says Amazon. Funny how on an amazon streaming device (I’ve used old stick to the newest firetv) there is no issue of adjusting the settings, but on a Roku is seems you get what you get when it comes to Amazon Prime video. Personally, I prefer the newest amazon firetv however they don’t offer AppleTv+ yet, so sticking with Roku for now. All these services and devices need to play nice, the inconsistency is super dumb.
Weirdly, changing the background opacity to 25% works fine on my old roku 3 and roku streaming stick+, but refuses to work on the roku ultra I bought a couple of months ago.
I'm having this problem as well. Subtitles work perfectly on every other application, I don't want to have to change my Roku settings every time I use prime only... wth amazon?
It's so dumb. I'm trying to watch Westworld through the HBO add-on and all of the first lines of in-show foreign dialogue subtitles get blocked by the Amazon Prime black box subtitles saying "(speaking German)", "(speaking Chinese)", etc.
The 25% opacity setting didn't even work for me.