This sounds more like an account reserve or payment risk control change than anything related to your forum question.

Amazon can hold part of the balance to cover refunds, claims or chargebacks, even if it feels sudden. It may also be separate from any charge showing on your bank account.

I would check three places first:

Payments / Statement View to see whether it says reserve, deferred transactions, or disbursement delay

Any performance or account health notifications around the same time

Whether the bank charge is actually a verification/subscription debit rather than the reserve itself

If a moderator sees this, the useful question is whether this was a normal reserve trigger, a verification-related hold, or a system-side payment control change.