Clone project not working on issue transition, but works with script console

[rajey]

I have a script which reads some custom fields to get the required information to clone a project.

Then I have the following code to clone the project (only relevant parts are shown):

// Bot user has admin access
// src, tar, and name is read from custom field as String
def copyProject = new CopyProject();
def user = ComponentAccessor.getUserManager().getUserByName("bot");
def inputs = [
(CopyProject.FIELD_SOURCE_PROJECT) : src,
(CopyProject.FIELD_TARGET_PROJECT) : tar,
(CopyProject.FIELD_TARGET_PROJECT_NAME) : name, 
(CopyProject.FIELD_COPY_ISSUES) : true, 
(CopyProject.FIELD_COPY_VERSIONS) : true,
(CopyProject.FIELD_COPY_COMPONENTS) : true,
]

ComponentAccessor.getJiraAuthenticationContext().setLoggedInUser(user);
copyProject.doScript(inputs);

When I run this script using the script console, I get no errors and the cloning works perfectly.

However I added my script to a workflow transition and every time the transition occurs my script fails.

Here is the error log that I can see:

java.lang.NullPointerException
at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:877)
at com.google.common.cache.LocalCache.get(LocalCache.java:3951)
at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3974)
at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4958)
at com.google.common.cache.LocalCache$LocalLoadingCache.getUnchecked(LocalCache.java:4964)
at com.atlassian.jira.issue.watchers.DefaultWatcherManager.isWatching(DefaultWatcherManager.java:134)
at com.atlassian.jira.issue.watchers.DefaultWatcherManager.updateWatch(DefaultWatcherManager.java:174)
at com.atlassian.jira.issue.watchers.DefaultWatcherManager.startWatching(DefaultWatcherManager.java:92)
at com.atlassian.jira.issue.watchers.DefaultWatcherManager.startWatching(DefaultWatcherManager.java:83)
at com.atlassian.jira.issue.watchers.WatcherManager$startWatching$0.call(Unknown Source)
at com.onresolve.scriptrunner.canned.jira.utils.AbstractCloneIssue$_copyWatchers_closure7.doCall(AbstractCloneIssue.groovy:413)
at com.onresolve.scriptrunner.canned.jira.utils.AbstractCloneIssue.copyWatchers(AbstractCloneIssue.groovy:412)
at com.onresolve.scriptrunner.canned.jira.utils.AbstractCloneIssue.execute(AbstractCloneIssue.groovy:249)
at com.onresolve.scriptrunner.canned.jira.utils.CopyIssueWithAttachments.super$4$execute(CopyIssueWithAttachments.groovy)
at com.onresolve.scriptrunner.canned.jira.utils.CopyIssueWithAttachments.execute(CopyIssueWithAttachments.groovy:25)
at com.onresolve.scriptrunner.canned.jira.workflow.postfunctions.CloneIssue.super$5$execute(CloneIssue.groovy)
at com.onresolve.scriptrunner.canned.jira.workflow.postfunctions.CloneIssue.execute(CloneIssue.groovy:135)
at com.onresolve.scriptrunner.canned.jira.workflow.postfunctions.CloneIssue$execute.call(Unknown Source)
at com.onresolve.scriptrunner.canned.jira.admin.CopyProject$_doCopyProject_closure13.doCall(CopyProject.groovy:601)
at com.onresolve.scriptrunner.canned.jira.admin.CopyProject.doCopyProject(CopyProject.groovy:580)
at com.onresolve.scriptrunner.canned.jira.admin.CopyProject$doCopyProject.callCurrent(Unknown Source)
at com.onresolve.scriptrunner.canned.jira.admin.CopyProject.execute(CopyProject.groovy:357)
at com.onresolve.scriptrunner.canned.jira.admin.CopyProject.execute(CopyProject.groovy)
at com.onresolve.scriptrunner.canned.AbstractCannedScript.doScript(AbstractCannedScript.groovy:81)
at com.onresolve.scriptrunner.canned.CannedScript$doScript$13.call(Unknown Source)
at add_project.run(add_project.groovy:94)

 
Can anyone suggest why I could be getting this error?