The Update Portal Integration Bundle was failing with a restman error.
Error Log Reference:
<l7:Mapping action="NewOrUpdate" errorType="UniqueKeyConflict" srcId="b4bff64ea3a845db60b78151a87dc037" type="POLICY">
<l7:Properties>
<l7:Property key="ErrorMessage">
<l7:StringValue>(name) must be unique</l7:StringValue>
</l7:Property>
</l7:Properties>API Developer Portal 5.4.x
Duplicate "API Plans fragment" on Gateway root directory.
Remove the duplicate "API Plans fragment" and re-run Update Portal Integration Bundle.