Odd hiccup in e-mailing sales order invoices in 2015 pu 2

Printed four invoices with the new feature of keep windows open after print / preview checked.   System was set to print and electronically deliver invoices.

The printing window stayed open as expected,   but then I mistakenly hit print a second time.   Despite the box for print invoices previously printed NOT being checked, it printed and e-mailed the invoices a second time.

Client then called me and indicated that the second round of invoices did send them the correct invoice but the information for customer name and invoice number in the e-mail were for the customer in the fourth invoice.   After calling around I determined this was true for all of the clients.

As I had not yet updated the invoice register,  I experimented and determined that the system was still e-mailing out all invoices with the information for the fourth invoice although I could not duplicate the problem the print invoice previously printed.

I didn't find any reports in the knowledgebase but that could be a matter of finding the correct keywords.

Anyone else notice anything similar to this?