There was a post before, but it was buried with no response from twitch. Was the v5 subscriber check quietly disabled? It has been broken for a few days, when looking up a user it returns the channel owner as a subscriber.

Twitch V5 Subscriber [BROKEN API]

Travis_Miller June 19, 2018, 5:18am 4

I have not changed my code for months, and this used to work…

Topic		Replies	Views
V5 Check Channel Subscription by User wrong sub_plan API	8	1699	August 20, 2018
Check Subscription by User endpoint returns my own channel subscription object API	17	3428	August 27, 2018
Check Channel Subscription by User is not respoding API	2	276	June 26, 2020
Last subscriber API	2	1520	July 11, 2018
Helix is not sending my subscriptions API	12	1116	September 3, 2019