A few weeks one of our streams stopped showing in the search list when I search by game. I can confirm on our end that nothing has changed with the way we are streaming.
I’m not particularly sure how Twitch’s search runs internally, but this may be due to your stream being in a glitched state with their search. Assuming they pipe streams into something like elastic search when they go live, perhaps your stream wasn’t indexed. I would try taking your stream offline for a short while (since it appears to be a 24/7 stream), then starting it up again to see if that helps.