I have tried Teamviewer14 between 3 Windows 10 computers - in pairs.
On every combination, I can only get internet audio in one direction. In every case, the computer doing the 'controlling' cannot hear the operator of the remote computer.
I have been through all the usual audio settings and all appears fine.
I have just tried swapping over between 2 computers (both running the latest Win10) in my own premises - and the problem 'reverses' with no other settings changed. This would appear to confirm that it is not a problem of my causing.