You aren't crazy. I just tried your fix and it worked for me, too! 3 days ago Bixby no longer could hear me. Then yesterday I was trying to order a pizza. I called 4 times and they could not hear me, but then I used my earbuds and she heard me. Then this morning a client called me twice & he could not hear me, even after powering off and back on. So I searched and found your "blow in the headphone jack" fix and now Bixby can hear me. Seems like a hardware defect to me.