When you start a subscription, only posts within 30 days before the subscription start date can access.  

You can access past postings exceed 30 days ago to buy unlock Ticket  

When you retain a subscription, you can continue to view posts for the duration of the subscription, and if you unsubscribe and re-subscribe, you can access only posts within 30 days prior to the new subscription date.

Subscription starts on July 1st -> Unlocks the post updated from June 2nd to subscription termination day.

Subscription starts on July 1st, terminates on August 31st, subscription starts again on October 1st, -> unlocks on September 2nd contents.