Live streams don't have captions
Livestreams say subtitles disabled when there are subtitles on other devices
I've also noticed this as well.
Vanilla YouTube and YouTube ReVanced allow us to enable closed captions for livestreams, but SmartTube Beta—what I'm using for my T.V.—won't let me enable them unless it's a VOD.
Same here. I can see the captions in stock YouTube, but they're marked "disabled" in STN.
+1 - this presents a big challenge and barrier to watching streams that have someone captioning something in real time (such as Google I/O). The captioning stream is present through YT itself and other apps, but not in STN. STN is a crucial app for accessibility for some, and that this is missing or otherwise absent is a big miss. (I imagine there's a reason for this, though it'd be good to know why.)