oneway audio after hold on T46

[hackin8]

We have a T46 that generally performs as expected, just one issue.

If a call is placed on hold and then resumed - occasionally the audio is oneway - we can still hear the other party breathing / talking - but they cannot hear us. Repeating placing on hold and resuming doesn't help, however if the call is then transferred to another extension it seems the audio works again.

No changes to standard setup - and problem occurs when using both the hard hold key and a programmed hold key.

Running latest version of firmware on system

Thanks