Exception in CSV importer when version not set

Given some simple CSV that does not set the Fix For or Affects version:

id,summary,description,bugzilla
1,ZZ,issue foo,1234
2,YY,issue bar,43321

JIRA's CSV importer correctly imports this, but the following is seen in the logs:

2005-05-12 13:14:38,834 ERROR [workflow.function.issue.IssueCreateFunction] An exception occurred
java.lang.NullPointerException
at com.atlassian.jira.issue.fields.AbstractVersionsSystemField.updateIssueValue(AbstractVersionsSystemField.java:423)
at com.atlassian.jira.issue.fields.AbstractVersionsSystemField.createValue(AbstractVersionsSystemField.java:442)
at com.atlassian.jira.workflow.function.issue.IssueCreateFunction.execute(IssueCreateFunction.java:80)
at com.opensymphony.workflow.AbstractWorkflow.executeFunction(AbstractWorkflow.java:1179)
at com.opensymphony.workflow.AbstractWorkflow.transitionWorkflow(AbstractWorkflow.java:1434)
at com.opensymphony.workflow.AbstractWorkflow.initialize(AbstractWorkflow.java:584)
at com.atlassian.jira.workflow.SimpleWorkflowManager.createIssue(SimpleWorkflowManager.java:143)
at com.atlassian.jira.issue.managers.DefaultIssueManager.createIssue(DefaultIssueManager.java:169)
at com.atlassian.jira.issue.managers.CachingIssueManager.createIssue(CachingIssueManager.java:82)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at com.atlassian.util.profiling.object.ObjectProfiler.profiledInvoke(ObjectProfiler.java:71)
at com.atlassian.jira.config.component.DelegatingInvocationHandler.invoke(DelegatingInvocationHandler.java:27)
at $Proxy2.createIssue(Unknown Source)
at com.atlassian.jira.external.ExternalUtils.createIssue(ExternalUtils.java:254)
at com.atlassian.jira.imports.importer.impl.DefaultJiraDataImporter.importIssues(DefaultJiraDataImporter.java:371)
at com.atlassian.jira.imports.importer.impl.DefaultJiraDataImporter.doImport(DefaultJiraDataImporter.java:83)
at com.atlassian.jira.imports.importer.impl.ImporterThread.run(ImporterThread.java:16)