Paying the minimum payment by the due date helps you avoid late fees and keeps your account in good standing – but it does not prevent from minimum payment admin charge.
Minimum payment admin charge is charged because the full statement balance was not paid. Once you pay less than the full amount, you lose the grace period, and admin charge is applied to the remaining unpaid balance starting from the transaction date.
To avoid minimum payment admin charge in the future, you must pay the full statement balance by each due date.