Stereo audio only playing (and exporting) out on left or right side

In the lastest versiosn of Premiere Pro Beta 24.1  a stereo music track when placed on audio track 1 is only plyaing and exporting audio out on the left channel.   If I drag it to track2 it only plays and exports the audio on the right channel.  If I drag it to a new (5th track) it plays on both sides - but then doesn't export any audio.