Epic Link value is stopping linked Issue field validation?

[Suresh]

When Epic Link has some value, following validation is working, if the Epic Link is empty then validation is failing.

We are validating against to the ('Linked Issues') -->Issue (multi select dropdown) not on Epic Link

Not sure I am calling from correct linked object?

def request = ActionContext.getRequest()

def params = request.getParameterMap()
 def issueLinkingValue = linksSystemField.getRelevantParams(params) as IssueLinksSystemField.IssueLinkingValue

def linkedIssue = it.destinationObject
 for(link in issueLinkingValue.getLinkedIssues()){
 def object = ComponentAccessor.getIssueManager().getIssueObject(link)
 cf1Value= (Option)object.getCustomFieldValue(featureType)
 if(cf1Value.getValue() != "High Pack"){
 throw new InvalidInputException(IssueFieldConstants.ISSUE_LINKS,
 "Note: When Cause equals 'HighPack'. You must link only High Pack.") 
 } 
 }