DSpace 6.3 OAI Indexing failure: unknown field 'item.willChangeStatus'

[Nason Bimbe]

Hello,
OAI indexing is failing on 6.3 with the ERROR below

[dspace]/bin/dspace oai import -c
OAI 2.0 manager action started
Clearing index
Index cleared
Using full import.
Full import
org.apache.solr.client.solrj.impl.HttpSolrServer$RemoteSolrException: ERROR: [doc=xxxxxxxxxxx] unknown field 'item.willChangeStatus'
        at org.apache.solr.client.solrj.impl.HttpSolrServer.executeMethod(HttpSolrServer.java:552)
        at org.apache.solr.client.solrj.impl.HttpSolrServer.request(HttpSolrServer.java:210)
        at org.apache.solr.client.solrj.impl.HttpSolrServer.request(HttpSolrServer.java:206)
        at org.apache.solr.client.solrj.request.AbstractUpdateRequest.process(AbstractUpdateRequest.java:124)
        at org.apache.solr.client.solrj.SolrServer.add(SolrServer.java:116)
        at org.apache.solr.client.solrj.SolrServer.add(SolrServer.java:102)
        at org.dspace.xoai.app.XOAI.index(XOAI.java:280)
        at org.dspace.xoai.app.XOAI.indexAll(XOAI.java:227)
        at org.dspace.xoai.app.XOAI.index(XOAI.java:134)
        at org.dspace.xoai.app.XOAI.main(XOAI.java:560)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.dspace.app.launcher.ScriptLauncher.runOneCommand(ScriptLauncher.java:229)
        at org.dspace.app.launcher.ScriptLauncher.main(ScriptLauncher.java:81)

Any idea of how I can fix it?

Best
Nason