user value of JiraAuthenticationContext not set is SOAP service getIssue()

Call to JiraAuthenticationContext.setUser missing during getIssue SOAP service call.
Service call will fail silently if there are custom fields with explicit secutity checking for attributes derived from current user.

In my case I try to verify existance of an issue using getIssue SOAP service which leads to creation of issue object which leads to creation of one paticular customfield where getValuFromIssue fails due to null value in ComponentManager.getComponentInstanceOfType(JiraAuthenticationContext.class)).getUser().

getUser() returns null because user is not set in getIssue Soap service call.