If the CA Directory DSA being used for the IM UserStore is configured with password policy enabled then the dxPwdLoginTime attribute will be updated to capture the login time of a user. If CA Directory receives a request to change one's own password the dxPwdLoginTime attribute will not be cleared, but if CA Directory receives a request to change the password of a user that is not submitting the request then the dxPwdLoginTime attribute value will be cleared. Since IM uses a proxy ID configured in the UserDir XML to perform all updates, CA Directory needs to have password-proxy-user set to that user in order for password changes from IM to not clear the dxPwdLoginTime attribute.