Monitor and ChangeMonitor on Asterisk 1.6.10

Hello,

I updated from 1.6.9 to 1.6.10 and the Monitor command (dialplan) with the “m” option does not work anymore. The 2 audio channels are not mixed when terminating call or calling StopMonitor. The use of ChangeMonitor has no effect, and no error is displayed.
Any idea or help ?

Thanks.