Call lands on speaker mode by default

[Naveen Nagpal]

My phone on its own decided to receive all calls on speaker mode by default. Its get even more awkward when I get call waiting, the ongoing call goes on speaker mode & everyone is able to hear my conversation until I disconnect the call or wait for the 2nd caller to disconnect. This started to happened when I updated all my apps (30 odd) at one go after a very long time, hence unable to pin down which app update may have caused this. I searched a few forums & applied a few solutions but none of them worked. Hoping someone here can help.