When printing an envelope, one of our users noticed that the first letter of the addressee's name printed as a 6th digit after the zip code. When the user opens a new 2007 document and prints and envelope, there is no problem. However, when she opens an old 2003 document in Compatibility Mode and edits the address (or types a new one), then the letter prints as a 6th digit of the zip code.
To print envelopes, the user opens the desired document, edits the mailing address, selects envelopes from the Mailing tab, and the preview looks good. There is no indication that it will print funny. Then, when they click print, the envelope prints with a letter after the zip code.