Asterisk, queues and VoIP cordless

Hi everyone hoping an asterisk expert can help me

We’ve successfully configured ring all style queues with sip extensions with various desk phones including Digium and polycom.

However with the Gigaset (C510/C610 from memory) and Panasonic (KX-TGP500B04) sip cordless phones with the SIP extension setup exactly the same as a desk phone on multiple versions of asterisk including 1.8 and 11 the queue starts by ringing all phones and would normally stop after say 6-8 rings pause and then repeat the ring all for another 6-8 rings until the queue times out or the call is answered. However with both cordless phones which I assume use different chipsets and software all phones ring to start I.e. mix of desk and cordless then the desk phones stop ringing as normal and the cordless keeps ringing. The desk phones don’t ever ring again in that queue like the cordless has stolen the call even though the call is not answered on the cordless it continues to ring.

Any ideas why this behaviour is seen with both sip cordless phones and never with sip desk phones.

You would need at least the SIP history for the calls to have any idea what is happening, however it sounds like a problem with the phones.