panning problem

I have seen other posts on this but no real resolution. Hoping someone has one.

This has happened twice on different tracks in same project.

I record mono on left and mono on right. I have the inputs set up correctly. At first I am able to pan the tracks normally.

But then later, sometimes next day , somtimes same day.. I am unable to pan at all. everything is straight up the middle. I do not have the stereo button pushed at all on any of the tracks this happens to.

It started on two tracks at first, I created two new empty tracks, and moved the wav files to them, and it was corrected. I deleted the now empty tracks.

Now it has happened on two different tracks. I know I can create two new tracks move the files and it will be corrected, but I have a feeling this is going to keep happening, and would not like to have to do this each time.

The two mono tracks are routed to a stereo bus. But logically that should have nothing to do with it.

No matter how I pan the two tracks. the console indicator does not change it is dead center, the panning indicator shows panned but the console view window for the peaks and all, dead center.

And yes, the track is not panning at all..

Any suggestions?