Streaming To Fb Audio Issues

hi folks,
i'm having issues w/ audio/video streaming to fb hosting from 'google meet' free ....
audio/video ok during the session on 'meet,' everyone can hear/see everyone else...

however, post session recording on fb has only host voice,
video recorded on fb after streaming ends is ok,
recorded fb audio has only host voice loud & clear,
participants/guests voices in the fb recording are gone,
slight hum w/ very very dim voices in the background fb recording can be heard at very high volume....

checked everything,
all other applications audio/video work ok,
virus scan daily,
all updated win 7/chrome/codecs/audio drivers ...

what could be the cause and what could help ?