Panning problem

Is it maybe a one-sided stereo track? When you look at the waveform, do you see a wave on top but just a solid line on the bottom half? If so, then you've accidentally recorded a mono source as stereo, but only on one side. Right-click on the clip and select "convert to mono".

That's a good one. We seem to always reach for the most exotic explanation while overlooking the simplest ones. Thanks for updating the thread with the resolution.