Can you give me a bit more detail? Your opponents LOS never shows or is the problem linked to specific situations? Plus, what versions are you using? If one of you is using 6.3.3 or earlier and the other is using 6.4.0 then that might cause a problem.
This is when playing back PBEM logs. It's happening in both games I've got currently underway. In both cases we're all using V6.4, however, the games originated with VASL6.3.3.
I never see the LOS string show up when playing back the log anymore. I used to. Hope that helps.