Looks like you are hitting this https://bst.cloudapps.cisco.com/bugsearch/bug/CSCux02069/?referring_site=bugquickviewredir
Please try installing latest ES for CUIC and see if it works.
https://software.cisco.com/download/release.html?mdfid=282163829&flowid=73207&softwareid=282377062&release=Leap_second&relind=AVAILABLE&rellifecycle=&reltype=latest
regards
Chintan