Environment and conditions:
1. SPA504G with 7.5.4 firmware
2. button configured like
fnc=cp+blf+sd;ext=4299@$PROXY;sub=4299@$PROXY
e.g. the button is monitoring the state of (other) line 4299
Now, someone is calling the line 4299. PBX notify the phone about it (<dialog id="4299" direction="recipient"><state>early</state></dialog>). Monitoring phone will play Call_Pickup_Tone, but then it will not turn the speaker off. It will continue to emit noise althougth phone is in idle on-hook state.
There are no syslog messages even at highest debug level during this phase.
The noise is almost unnoticeable in casual office, but very annoying in silent room. Playing with Call_Pickup_Tone has no efect. Noise will not stop even when monitored line become idle.
The noise can be stopped by ->off-hook ->on-hook transition only.
It seems to be firmware bug. Is there a known workaround for such bug ?
