Why are phones re-registering - NOTIFY restart message?

[joe.loiacono]

Trying to figure out why phones keep re-registering. Looks like the SIP NOTIFY message below is asking the phone to restart (action=restart) it's previous REGISTER attempt. Anyone know why? Thanks.

NOTIFY sip:80233246711@10.76.62.46:48514 SIP/2.0
Via: SIP/2.0/TCP 10.161.193.136:5060;branch=z9hG4bK2213274554a44
From: <sip:10.161.193.136>;tag=1325191918
To: <sip:80233246711@10.76.62.46>
Call-ID: 73fe8d80-66710ed0-14bb82-88c1a10a@10.161.193.136
CSeq: 101 NOTIFY
Max-Forwards: 70
Date: Tue, 08 Dec 2015 17:09:36 GMT
User-Agent: Cisco-CUCM10.0
Event: service-control
Subscription-State: active
Contact: <sip:10.161.193.136:5060;transport=tcp>
Content-Type: text/plain
Content-Length: 82

action=restart
RegisterCallId={c80084ec-1991058b-23147096-225811b6@10.76.62.46}

[joe.loiacono]

(Sorry - left out some more info:)

Here's the following SIP REGISTER request

REGISTER sip:10.161.193.136 SIP/2.0
Via: SIP/2.0/TCP 10.76.62.46:48514;branch=z9hG4bK2895e49e
From: <sip:80233246711@10.161.193.136>;tag=c80084ec199106a91d471e34-4e3789b1
To: <sip:80233246711@10.161.193.136>
Call-ID: c80084ec-1991058b-23147096-225811b6@10.76.62.46
Max-Forwards: 70
Date: Tue, 08 Dec 2015 17:09:36 GMT
CSeq: 1123 REGISTER
User-Agent: Cisco-CP8945/9.4.2
Contact: <sip:6ecc3d71-f708-9e98-0fe1-2d16a51e801e@10.76.62.46:48514;transport=tcp>;+sip.instance="<urn:uuid:00000000-0000-0000-0000-c80084ec1991>";+u.sip!devicename.ccm.cisco.com="SEPC80084EC1991";+u.sip!model.ccm.cisco.com="585"
Supported: replaces,join,sdp-anat,norefersub,resource-priority,extended-refer,X-cisco-callinfo,X-cisco-serviceuri,X-cisco-escapecodes,X-cisco-service-control,X-cisco-srtp-fallback,X-cisco-monrec,X-cisco-config,X-cisco-sis-7.0.0,X-cisco-xsi-8.5.1
Content-Length: 0
Reason: SIP;cause=200;text="cisco-alarm:23 Name=SEPC80084EC1991 ActiveLoad=SIP894x.9-4-2SR1-2 InactiveLoad=SIP894x.9-4-2-8 Last=reset-restart"
Expires: 0

and then the final bad news the RST,ACK:

(see attached)