Cisco 3905 T302 timer issue

[krizvite]

Hi Community, 
I have one issue regarding CP-3905 phones. If I call overlap, so take handset and try to call some number. After first digit pressed the cucm start call routing. Other phones like 88XX or 78XX work fine. They wait t302 timer before cucm start call routing.

I have configured Phone SIP Dial Rules on the CP-3905 and after that the call routing on the CP-3905 started working.
Do you have any explanation why the CP-3905 dont wait the t302 timer?

CUCM 12.5SU3, newest FW of the phone from 2018

[krizvite · Accepted solution]

This looks like a bug. Phone SIP Dial rules helped me. I have opened a tac case and cisco will open a bug case to this topic.