Well, if I look at the details of the original invoice, the Document Date is 03/12/09. However, in the middle "applied" section (i.e. where it shows what payments and/or adjustments are related to the invoice) it shows a Credit Note with an Applied Amount of (100.03) and a Date of 11/14/43 and a Payment with an Applied Amount of (34.24) and a Date of 03/19/09.

When I go to the Credit Note details, the Document Date is 03/16/09. However, in the middle "applied" section, it shows the invoice with an Applied Amount of 100.03 and a Date of 11/14/43.

So looking at the transaction detail for the invoice and the credit note, they both have Document Dates in March 2009. However, when looking at what was applied to each of those transactions that is where the 2043 date is appearing. In running the vendor transaction report there is nothing with a processed date of 2043, it seems only that the date that the transactions were "applied" to one another was done in 2043. I have no idea if A/P works the same way as A/R in that you can enter an invoice and then a subsequent payment and/or adjustment and then subsequent to that apply them against each other with some other date, but that seems to be what is happening.

As it stands right now, the transaction has been fully "offset" so the outstanding amount should be zero (at end of March 2009) however the system believes the credit note is not being applied until 2043 so that the outstanding payables are being reported as 100.03 higher than they should be, and will continue to report at this inflated amount until Nov 2043.

The only thing I can think is that the System Date was changed to 11/14/43 when the processor of this transaction logged into Adagio A/P. I have looked at the posting journal for the credit note and everything looks normal. Is there any way to check what system date was used when a particular transaction was created? Is it the system date that determines the "applied" date of a transaction to another transaction? The credit note is part of a larger batch of transactions, although they could have been entered over a period of time (such as a week) with different system dates.
The transactions have all gone to GL in March - invoice with date of 03/12/09, credit note with date of 03/16/09 and payment with date of 03/19/09, which matches the individual Document Dates in A/P.

It is very strange.