How can I defer the actual charge until capture when using authOnlyTransaction and priorAuthCaptureTransaction with authorize.net?

I'm trying to implement a deferred payment system using authorize.net's "Authorize a Credit Card" (authorize) and "Capture a Previously Authorized Amount" (capture) functionalities with the following transaction types:

• Authorization: authOnlyTransaction
• Capture: priorAuthCaptureTransaction

My plan is for the authorization step to place a hold on the funds without immediately charging the card, and then to process and record the charge only when the capture is executed within the 30-day validity period.

However, I’ve noticed that as soon as I call the authorize endpoint, the issuing bank immediately processes the charge and the transaction appears in the billing records—even though I haven't executed a capture yet. When I subsequently void the transaction, it refunds an already processed payment.

Could there be any account settings or API configuration issues causing the authorization to finalize the charge immediately? How can I adjust my implementation so that the charge occurs only when the capture is executed?

Any insights or suggestions would be greatly appreciated.