You're correct that the original transaction did not hit the GL account for AP at all. The original distribution was a debit to the PURCH account and a credit to the CASH account.
When I voided the payment, it created a debit to the CASH account and a credit to the AP account. That's why the voided payment shows up in the matched transaction section.
When I voided the invoice, it created a credit to the PURCH account and a debit to the AP account. That's why the voided invoice also shows up in the matched transaction section.
I didn't edit the distributions at all when I voided the payment and the invoice; GP made those entries automatically, and I'm pretty certain that it made the proper GL entries.
So I understand why the original transactions are not matched in GL (because they weren't in the payables GL in the first place.) What I don't understand is why they add up to $(18.00) instead of $0. Both of those unmatched transactions are negative; I think one of them is supposed to be positive.
Lee