To expand a bit on this, in V14 when you press the DND button on a deskphone that has been provisioned using a Default Template 2 things happen:
1) The Extension Profile is set to "Do Not Disturb".
2) The deskphone activates DND.
Also Ring Groups and Queues ignore Forwarding Rules in the "Away" and "Do Not Disturb" statuses except "Send call to my mobile" and "send call to external number". This means that if you are in e.g. "Do Not Disturb" status and have "Send calls to my Voice Mail" without having the DND function on the phone enabled, if the calls comes to this extension through a Ring Group it will ring normally.
Now combining the above 2 points, what is happening is:
- Call comes into the Ring Group.
- Extension is in "Do Not Disturb" status but it is ignored so the PBX sends the call to the extension, but because the actual DND function is also activated on the phone, the phone rejects the call.
- Because you also have a mobile device with the same extension, the PBX also sends the call to this one as well, this device however does not have a DND function to bounce the call so it rings.
Hope this explains why it is happening.