Exporting to PDF does not work correctly with #includeForm

1 TEST
This is a test

1 TEST
This is a second test

#includeForm("Main.TestPDF1")
#includeForm("Main.TestPDF2")

Wrapped Exception: Error number 12002 in 12: Exception while exporting PDF
Wrapped Exception: org.apache.fop.fo.ValidationException: null:19:240: Property id "HTEST" previously used; id values must be unique in document.
com.xpn.xwiki.XWikiException: Error number 11015 in 11: Exception while exporting
Wrapped Exception: Error number 12002 in 12: Exception while exporting PDF
Wrapped Exception: org.apache.fop.fo.ValidationException: null:19:240: Property id "HTEST" previously used; id values must be unique in document.
	at com.xpn.xwiki.web.ExportAction.render(ExportAction.java:64)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:198)
	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:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
        ...