"Exception while patching" error

Working with 1.2.6932. New documents "seem" to work fine "for a while": you can access revisions and make comparisons without problem during some time, then any URL including ?rev= throws the following exception:

Error number 3103 in 3: Exception while reading document version

{1}
Wrapped Exception: Error number 13027 in 13: Exception while patching
Wrapped Exception: line::java.lang.NumberFormatException
com.xpn.xwiki.XWikiException: Error number 3103 in 3: Exception while reading document version {1}

Wrapped Exception: Error number 13027 in 13: Exception while patching
Wrapped Exception: line::java.lang.NumberFormatException
at com.xpn.xwiki.doc.XWikiDocumentArchive.loadDocument(XWikiDocumentArchive.java:319)
at com.xpn.xwiki.store.XWikiHibernateVersioningStore.loadXWikiDoc(XWikiHibernateVersioningStore.java:162)
at com.xpn.xwiki.XWiki.getDocument(XWiki.java:1060)
at com.xpn.xwiki.web.XWikiAction.handleRevision(XWikiAction.java:257)
at com.xpn.xwiki.web.ViewrevAction.render(ViewrevAction.java:29)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:148)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:228)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:216)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:634)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:445)
at java.lang.Thread.run(Unknown Source)

Wrapped Exception:

com.xpn.xwiki.XWikiException: Error number 13027 in 13: Exception while patching
Wrapped Exception: line::java.lang.NumberFormatException
at com.xpn.xwiki.doc.rcs.XWikiPatch.patch(XWikiPatch.java:177)
at com.xpn.xwiki.doc.XWikiDocumentArchive.getVersionXml(XWikiDocumentArchive.java:332)
at com.xpn.xwiki.doc.XWikiDocumentArchive.loadDocument(XWikiDocumentArchive.java:304)
at com.xpn.xwiki.store.XWikiHibernateVersioningStore.loadXWikiDoc(XWikiHibernateVersioningStore.java:162)
at com.xpn.xwiki.XWiki.getDocument(XWiki.java:1060)
at com.xpn.xwiki.web.XWikiAction.handleRevision(XWikiAction.java:257)
at com.xpn.xwiki.web.ViewrevAction.render(ViewrevAction.java:29)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:148)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:228)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:216)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:634)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:445)
at java.lang.Thread.run(Unknown Source)

Wrapped Exception:

java.lang.NumberFormatException: For input string: " "
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at com.xpn.xwiki.doc.rcs.XWikiPatchUtils.patch(XWikiPatchUtils.java:89)
at com.xpn.xwiki.doc.rcs.XWikiPatch.patch(XWikiPatch.java:175)
at com.xpn.xwiki.doc.XWikiDocumentArchive.getVersionXml(XWikiDocumentArchive.java:332)
at com.xpn.xwiki.doc.XWikiDocumentArchive.loadDocument(XWikiDocumentArchive.java:304)
at com.xpn.xwiki.store.XWikiHibernateVersioningStore.loadXWikiDoc(XWikiHibernateVersioningStore.java:162)
at com.xpn.xwiki.XWiki.getDocument(XWiki.java:1060)
at com.xpn.xwiki.web.XWikiAction.handleRevision(XWikiAction.java:257)
at com.xpn.xwiki.web.ViewrevAction.render(ViewrevAction.java:29)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:148)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:228)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:216)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:634)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:445)
at java.lang.Thread.run(Unknown Source)