Over the last week and a half we have noticed a strange phenomenon. Some invoices are printing (and posting, if not caught) with the date 6/20/07. The first time we noticed it, they were supposed to be dated the 22nd, and it seemed reasonable to think that there was a keying error somewhere, although there were several that were also dated the 22nd like they were supposed to be, so it was not universal.
 
Upon further research I have found that this has happened a few times before, where, for two or three weeks random invoices get printed and posted with a previous date. For instance, from 1/10 - 1/26/05 a bunch of invoices posted with the date 1/6/05.
 
The only thing that SEEMS to be in common (but not exclusively) is that they are ones that do not have Packing Lists printed with the ship date on them. Since we do not enter a date in SO-E when releasing (we leave it blank), maybe that is getting messed with somehow.
 
This is our normal flow:
Enter SO, not ready to invoice
Print Pick List, without ship date
Later on, possibly several days:
Release SO, leave ship date blank
Optional --> print Packing List (no packing list for CODs or Credit Card invoices), over-ride existing ship dates* with "today"
Print Invoice
Following day:
Post Invoices
 
One last thing. We almost never close DBA/Evo, so the date displayed on the status bar is often many days/weeks in the past. I thought I had hit upon that as the reason, but I checked, and the date on the workstation that processed this last series of invoices is on 6/19/07 and the date they are being posted for is 6/20/07.
 
The one thing I am quite sure of, since we started checking this a few days ago, is that the original invoice is printing with the wrong date. If we catch it there we're fine. It's not in the posting process.
 
* I've checked several of the invoices from this last batch, and 6/20/07 is not on them anywhere. Not estimated ship date, not customer due date, WO start/complete (if applicable - some do have WOs, some do not). Nothin.

The Ship Date is saved to the Sales Order header (BKAR.INV.SHIPDT) and could be cleared out using UT-K-B (once all pending invoices are posted) if it was mistakenly set as in this case.