Problem with DJM900nexus auto bpm detection

Hi, I am having a strange issue that I have never noticed before. We have CDJ2000's hooked into the DJM900 thru digital ports. when we have someone running serato separately, through RCA connections, the BPM detection no longer works. It seems as if it continues to analyze the BPM from the digital signal (which is just timecode noise), even tho the channel selector for that channel is on CD/Line, not digital. the FX section channel selector is set to master, and the auto button is engaged. What is even stranger, is if we hook up turntables with serato into the channels, the BPM still is reading an inaccurate time (with CDJ's still hooked into digital ports, but nothing playing thru them and the channel selectors set to CD/Line). and when I say inaccurate, I mean like off by 80 bpm. It is stuck to whatever BPM was coming into the mixer before switching from CD/Line.

We have 2 cdj2000's with digital connections, on channels 2&3 of the DJM, all linked, including into the mixer. if I put a RCA into channel 4, the BPM detects it fine, but if I put it into channel 3, it does not read the bpm properly (it reads whatever is sending out the digital on that channel, even tho the selector is on CD/Line & not digital)

any thoughts? anyone else able to test this?