Personally, I handle this situation by verifying the created_at leaf and creating a window for re-subscriptions even after twitch’s system disconnects it.
Long story short, temp store and verify the leaf on the due date and for a week after (i do it every 24 hours anyway irrelevant of the timestamp). If they resub during twitches window it won’t change within that week, if it does then you can just “perma” store the original and link them in your application. Some may consider it “hacky” but it works fine and doesn’t require anything from a third party.
/shrug