Ken, the controller is a 1769-L32E r19.011, and there *is* a 1769-SM2 in slot 2 as well as a 1769-SDN in slot 1.
LINX version is 3.80
The first time I browsed to it, it showed me the SM2 in slot 1 without the SDN card at all, but because I was just doing an SDN audit on a bunch of lines I'm not yet fully familiar with, I just figured the documentation was wrong and made a note of it. It wasn't until I was informed by my boss that there WAS an SDN on that line and went out to the line with my laptop to hook up locally that I saw the SDN on LINX and realized how weird this whole thing is.
I'm told this line has had really quirky comms problems since it's inception. It's also been known to have all its IO comms just freeze up if someone simply browses to it in LINX at the wrong time. Literally all you have to do is drill down into the IO and it will get so tied up that you need to power cycle the PLC to get it to start working again.
But it's an automotive plant with lots of fires to put out all day every day and not enough firemen, so the mentality up until this point has been "just don't touch it and it will keep working" haha. I just hired into the building to add some much needed assistance on the programming front, so hopefully we will be able to start dealing with intermittent problems like this in the near future.
