It sounds like a corrupted update. I would ask to have the tech "Altboot" the device. This would overwrite it and eliminate any corruption.
To be clear, there are no Firmware/Softwares that cause this issue, and there are no drivers that do so either. So the same software that resides on the device now is fine, it just needs to be ALtbooted.
About a month ago, a technician who was out to fix a hardware issue, upgraded the software/firmware on our WorkCenter 7556 copier. Ever since then we've had problems with 2-sided printing. I printed a 28 page word document today and selected 2-sided, one staple. The 1st two pages were back-to-back, pages 3 - 7 were single sided, pages 8 - 28 were 2-sided. It doesn't seem to matter if it is a word, pdf, etc. document and it seems to be completely random as to when it happens. It will work fine one time and the next time we print the same document, it won't work correctly. Any help would be appreciated.