Muffled sound for listener after switching back from speaker phone mode.

I searched through this forum and others to see if anyone was having this problem. Not sure if it's a hardware or software problem.
If software, I would presume that every owner of a 920 has this bug.

Anyways, what happens for me is, when I'm talking to someone using the 920 in normal talk mode, when I switch to speaker phone mode
and then switch back to normal talking mode, the listener on the other end says my voice now comes through all muffled. When I then switch
back to speaker phone mode they said it was fine. Thus, something is happening to the mic with the transition? It works fine before the switch
to speaker and back, but something causes the mic to send a muffled speach to the other user.

Anyone else experiencing this?

Reproduction steps:
1. Talk to another user using normal talk mode
2. Switch to speaker phone
3. Switch back to normal talk mode
4. Does other user complain/notice of a muffled/poor voice?