I only have a small personal use Brother printer, but I have noticed that it “jams” a lot when I print duplex too. The thing is with mine, it is not actually jamming. This happens to me when I print something duplex that only needs to print one side. The printer seems to want to suck the paper back in and flip it as if to print the other side even if there is nothing to print there, so if I take the sheet out when the first side is done printing but before it has a chance to suck it back in and flip it, it reads a false paper jam. The only thing I have to do is hit the X on the control panel and everything goes back to normal. I apologize if this is not applicable to your specific printer, but I thought there was a chance it may be a similar programming issue and not a physical jam after all.