Are you using mkvs? If so are subtitles set to default enable?
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Not 100% sure, but I believe you can change settings for the USER so regardless of client used, the default for subtitles is off.
Try using your computer to log in to the same user account, then change some settings there.
Edit: Once logged in using your browser, click on the user icon at the upper right, subtitles, then set subtitle mode to none. I suspect this will do the trick for you.
Awesome, I'll give it a go. Thank you. It only seems to be on the android TV Client, the same user on the desktop version, or the android app, or findroid, doesn't have the same issue, lol.