Extension name Persistence

First off I am using Asterisk ver 1.6.2.17.3 (I know old version but I have Aastra 9133i phones which will not go on hold with later versions) and FreePBX ver 2.8.1.5. My problem is when a person leaves and their extension is assigned to the new person taking their place, the old persons name is still displayed on the extension being called. Example: extension 137 was assigned to John X and now is assigned to Brittany F. When extension 116 is being called from 137 the number 137 is displayed on 116’s phone with John X’s name on the line below. I also have 2 other extensions that are doing the same thing. I have rebooted the server, set the phones back to factory default and let the new configuration file update to the latest user. I also removed the extension from asterisk re-loaded then re-created the extension but still the same result. Below is the sip trace when ext 116 is being called by 137.

[Apr 18 07:20:47] VERBOSE[5027] chan_sip.c: — (11 headers 0 lines) —
[Apr 18 07:20:47] VERBOSE[12285] app_dial.c: – SIP/116-00000003 is ringing
[Apr 18 07:20:47] VERBOSE[12285] chan_sip.c:
<— Transmitting (NAT) to 192.168.13.28:5060 —>
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP 192.168.13.28:5060;branch=z9hG4bK82c3c2be7;received=192.168.13.28
From: Brittany F sip:[email protected]:5060;tag=064323be98545bf
To: 116 sip:[email protected]:5060;tag=as2833ac7e
Call-ID: [email protected]
CSeq: 1768656801 INVITE
Server: FPBX-2.8.1(1.6.2.17.3)
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO
Supported: replaces, timer
Contact: sip:[email protected]
Content-Length: 0

Since this is not the only extension behaving this way there must be something I am missing. Hopefully someone out there has the remedy.

Thank You