According to the latest data, some time ago cupertinos changed the rules of the subscription in the App Store. In particular, Apple added an extra step that needs to protect users from accidental taps and unwanted fees.
Judging by the screenshot, which is published by another Twitter user, iOS 12.3 when you subscribe the owners of Apple devices should reaffirm their desire to use this service.
Thus, the cupertinos are trying to protect users from accidental subscriptions. A new window warns Apple device owners stating that the monthly subscription fees will be charged as long as the service will not be disabled in the menu “Settings”.
In addition to this additional step will prevent the developers who are trying to force people to fraudulently apply for a paid subscription to your application.