Brad,
What firmware version are you running on the phones? See the post below which indicates this is resolved with the Enhanced Line Mode features available in firmware 11.5(1). The release notes below say 11.5(1) is compatible with CUCM 10.5.2. Hope this helps.
https://supportforums.cisco.com/discussion/13015821/88418851-prime-line-auto-line-select-and-caller-id
Cisco IP Phone 8800 Series Release Notes for Firmware Release 11.5(1)
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cuipph/8800-series/firmware/releasenotes/p881_b_cisco-ip-phone-8800-series.html#reference_C0581B37033CCE5B7DB882BC338DC886
Brandon