Cisco CME CUCME "MAC address is already assigned with ephone" and DECEASED state

Customer complained that a Cisco 7941 on the CME would occasionally drop calls and reboot, also interupting pass-thru data connectivity.

After testing the physical layer between the phone and CME, we decided to replace the device with a spare as the original showed evidence of being treated with some disrespect.

It seems the method to do so would be to modify the MAC address in the ephone configuration, but of course that's more difficult than should be.

; let's get rid off the configuration related to the replacement phone
CME(config)#no ephone 24

; let's put the mac address of the replacement phone in the 
; ephone configuration of the faulty phone 
CME(config)#ephone  17 
CME(config-ephone)#mac-address 0011.2B2B.B9B9
;  be startled that you can't do this
MAC address is already assigned with ephone 24.
Can not assign same MAC address with mutilple ephone.

Ultimately what seemed to work was re-configuring ephone 24 with a dummy MAC, and then configuring ephone 17.

CME(config)#ephone  24 
CME(config-ephone)#mac-address aaaa.bbbb.cccc
CME(config)#ephone  17 
CME(config-ephone)#mac-address 0011.2B2B.B9B9

Now, to confuse the issue, the replacement device now registered as ephone 17 exhibits the same disconnect and reset symptom.  When running show ephone, the state of ephone-17 shows DECEASED.  That looks bad.

The official description of that state is:

The Cisco Unified IP phone is active and registered. Alternative states are UNREGISTERED (indicating that the connection to the Cisco Unified IP phone was closed in a normal manner) and DECEASED (indicating that the connection to the Cisco Unified IP phone was closed because of a keepalive timeout). 

With that, if the keepalive attempts are timing out it still seems there may be a network issue.  Given the cabling was tested, and the switch configuration simplicity and lack of errors, I doubt it, but we'll see.

As a test, I now removed any evidence of ephone 17 and ephone 24, created a new ephone 25 with the MAC address of the replacement phone, re-created the cnf files under telephony-services, and am monitoring the situation.