Why does my cm2320fxi start duplexing randomly?

[CLMCS]

One of my clients has a CM2320fxi MFP.  Recently when they've been using it as a copier, the device has been automatically switching over to duplexing mode on its own.  If they put a single sheet in the top tray to copy the feeder pulls it thru to copy the front of it, and then it sucks it back into the feeder to scan and print the back side of it.  They may have just made a copy of a document immediately before on the single sided setting and it worked fine, and then without touching any of the settings options it will duplex the next thing that they try to print.  It doesn't happen every time, it's just totally random when it decides to jump into duplex mode.  In the web interface of the printer it's set to do singe sided by default

I've upgraded the firmware to the latest version availble yesterday, and it still does this behavior. 

Has anyone seen this before or have any ideas how to get it to stop changing its settings on its own?

Thanks.

[SeanS]

Hey there! Looks like you are using a commerical printer I've linked below the direct link to the LaserJet section of the Business Support Forum. You will get a much better response over there. Good luck!

http://h30499.www3.hp.com/t5/Printers-LaserJet/bd-p/bsc-413