EFIS COMP MON message

[Lauramks2]

My research tells me that this message shows up when there is more than 10 knots difference between the airspeed at the pilot side and the copilot side. It is amber and most of the time I have ignored it but sometimes it affects the autopilot and kicks me back to "ROLL" mode. Took me a few approaches to figure out why I was moving off track. Took me longer to realize I needed to hit APR mode again. Now that I have figured out how to compensate, I am wondering if this happens to others. Is it a glitch or is something causing it. I thought it might be ice in the pitot but probe heat was on. It is irritating at worst and doesn't change my flying much but if anyone has some insight, I would appreciate it. If this happened for real, would I switch to a different ADC on the reversionary panel?