Hi,
Mahmoud gives good advice! More specifically, someone likely looked at the distributions and then entered the payment. The distributions are set (and therefore the distribution types) as soon as you open the window. You probably have a distribution type of PAY next to the accounts payable account. The account should most likely be cash (unless you paid it with a credit card) and the distribution type should be cash. This what a distribution window looks like when the voucher was paid at the time of entry:
Image may be NSFW.
Clik here to view.
Kind regards,
Leslie