BLF randomly stops working, SIP 7861 phones, CME

Hi All,

I was hoping somebody else out there may have experienced the following issue.

I have 18 SIP 7861 SIP phones setup with BLF speed dials. For some reason, the BLF status lights will start reporting wrong information. The speed dials will continue to work but the lights will essentially be out of sync.

If the handsets are rest, BLF status begins reporting correctly again however it stops working about a day or so later.

I have tried updating the phone firmware to a known stable version, I have uploaded a special IOS version provided by TAC. I have made sure the presence subscriptions are not over subscribed. However the issue begins to occur. I do have a case open with TAC and it's been open for going on 6 months now but I just wanted to reach out in case somebody else happened to have suffered from the same issue and knew a fix that I have not yet tried.

Phones are running the following firmware - sip78xx.11-5-1-18

Cisco 2901 CME is running c2900-universalk9-mz.SSA.test image provided by Cisco.

Appreciate any help.

Thanks