Since some api requests require certain scopes, sending an oauth token for those is required, and “just send a client ID every time” is redundant, as then both the client ID and the token would identify the same account (or what would happen if they were for different accounts?). Also, as LiraNuma said, DallasNChains explicitly said that we do not need to send a Client-ID if we already send an oauth token:
If you are passing in an OAuth token, we will figure out the Client-ID for you.
It appears it is also returning the same result in v3 whereas in the past it would return the expected result - even on Kraken root https://api.twitch.tv/kraken it isn’t pulling clientID from OAUTH, so I am thinking it may be a bug as well.
Hmm how odd, I generated that one to specifically test this and I got the results I mentioned above, however I just disconnected that one (thus invalidating it) and created a new one and the endpoints are working as expected, including V5.
So, i’m not sure if there is a intermittent issue but I am seeing all expected results using OAUTH, so that may be the issue with @LiraNuna - invalidate the current OAUTH and try again - that endpoint is now working for me.