<<<unlink the stereo tracks by pressing OPTION-L....>>>
What he said. The early days of broadcasting proved absolutely that the announcer voice should never be in actual stereo. Too many people drove off the road when the KFOG announcer leaned over to get a tissue and his voice went crazy in their cars.
Dual mono is perfect because the voice seems to be coming from the center.
There is a place for actual stereo. If you have a panel of respected speakers, you can *Cheat Slightly* to match the position of the speaker at the table. After they start talking for real and their picture goes center, the voice should, too.
There is a group of audio people who insist that voices always come from the center and just the room tone be in stereo. That works.
I was sure you were going to ask how to match the sound from the lavalier with the mic on the camera.
Koz