Text edits, generally adding notes to document. Edits were done with Acrobat Pro. Unfortunately, the behavior is inconsistent. We had the same user make changes to the original PDF again using same PC and Acrobat copy and the barcodes were unchanged.
The only difference i could see is the barcode is created on a PC with the font installed. the font is then embedded in the document. The original has the font embeded one time, the bad edit has the barcode embedded several times. When testing again the edited document only has the font embedded one time. I could see this causing a problem generating the barcode, which it doesn't, but i can't see it changing the underlying number of the barcode.