Problem on issue created event on transition

[Adrien MICHEL]

Hello,

I have a custom script that create another issue in a different board but the same project when a transition is trigger. But i've got the same error everytime. The issue is created but the link isn't created between the two issues.
i've disabled all the plugin i'm using on this environnment but this error keep poping up. Same for the 'string cast on applicationUser', i can't find where this error come from. Didn't find a lot on internet either. 

Thanks ! 

here's the error : 
com.atlassian.jira.exception.CreateException: com.atlassian.jira.workflow.WorkflowException: Error occurred while creating issue. This could be due to a plugin being incompatible with this version of JIRA. For more details please consult the logs, and see: http://confluence.atlassian.com/x/3McB
at com.atlassian.jira.issue.managers.DefaultIssueManager.createIssue(DefaultIssueManager.java:515)
at com.atlassian.jira.issue.managers.DefaultIssueManager.createIssueObject(DefaultIssueManager.java:604)
at com.atlassian.jira.issue.managers.RequestCachingIssueManager.createIssueObject(RequestCachingIssueManager.java:209)
at ASK_ajout_perimetre.run(ASK_ajout_perimetre.groovy:193)
Caused by: com.atlassian.jira.workflow.WorkflowException: Error occurred while creating issue. This could be due to a plugin being incompatible with this version of JIRA. For more details please consult the logs, and see: http://confluence.atlassian.com/x/3McB
at com.atlassian.jira.workflow.OSWorkflowManager.createIssue(OSWorkflowManager.java:765)
at com.atlassian.jira.issue.managers.DefaultIssueManager.createIssue(DefaultIssueManager.java:506)
... 3 more
Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to com.atlassian.jira.user.ApplicationUser
at com.atlassian.jira.issue.customfields.impl.UserCFType.getDbValueFromObject(UserCFType.java:83)
at com.atlassian.jira.issue.customfields.impl.AbstractSingleFieldType.createValue(AbstractSingleFieldType.java:138)
at com.atlassian.jira.issue.fields.ImmutableCustomField.createValue(ImmutableCustomField.java:692)
at com.atlassian.jira.workflow.function.issue.IssueCreateFunction.execute(IssueCreateFunction.java:81)
at com.opensymphony.workflow.AbstractWorkflow.executeFunction(AbstractWorkflow.java:1014)
at com.opensymphony.workflow.AbstractWorkflow.initialize(AbstractWorkflow.java:606)
at com.atlassian.jira.workflow.OSWorkflowManager.createIssue(OSWorkflowManager.java:741)
... 4 more

[Nic Brough -Adaptavist- · Accepted solution]

There's a line here that says

ASK_ajout_perimetre.run(ASK_ajout_perimetre.groovy:193

That strongly suggests that you have a groovy script installed in your Jira system, being run either as a validator or post-function on the "create" transition, and the script is not right for your version of Jira.

Have a look at the workflow to try to find it.