Some buddies appear "idle" - should be "available"

[Lee B.]

I have several buddies who always appear "idle," even when they are 
using the keyboard. I can contact them, but they appear "idle."

They are all using Windows XP
They are all using MSN protocol
They all use OTR (if that matters)

Others buddies with these same attributes appear normal ("available" 
when they are at the keyboard)

Is there something I can check or change to rectify this "idle" problem?