Mystery lines appearing in a/r invoice history after updating

Client has been noticing instances where a miscellaneous charge has been appearing in invoice history that were not on the original invoice.

The updated invoice appears in paperless office without the extra lines.

In invoice history inquiry, the extra lines are present but not included in the total of the invoice which suggest they weren't there originally.

So it would appear that these were created during updating, possibly some sort of cross link?  Hunting through other invoices on the same date do not show any similar lines.  I expanded the search to include two weeks prior to the invoices in question and found no matches for these lines.   Oddly enough the miscellaneous charge codes are items that are no longer used.  History in miscellaneous item maintenance shows no activity going back 20 years.

The extra items don't show in sales order history inquiry either.

Client indicates they are noticing them more often (or maybe they are just aware of it and watching for it now).

Looking in DFDM,  the lines are definitely present.  Did a rebuild keys files and sort files to hopefully avoid any future occurrences.

This is 2017.3.  Next step will be to apply the latest update.

I haven't spotted anything in the knowledgebase but it's a bit hard to describe in search times.  I don't see anything in product update notes either.

Anyone else seen anything like this?