I’ve successfully subscribed to and am processing the Stream Changed webhooks for various users. I’ve noticed that stream title changes aren’t being published after an initial period, i.e. I get updates for title changes within the first 20 minutes or so of the stream, but not later changes. I haven’t had any problems getting game changed notices.
A recent example: the channel SpeedGaming started streaming at about 5:50 pm Eastern today (Jan. 2). The stream title changed around 6:45 but there was no notification published to my subscription endpoint.