as of rev. 13159, when a template has a contentNodeIterator setup like this:

<cms:contentNodeIterator contentNodeCollectionName="mainContent">
<cms:editBar/>
<cms:includeTemplate></cms:includeTemplate>
</cms:contentNodeIterator>

It throws an NPE:

java.lang.NullPointerException
at info.magnolia.cms.taglibs.ContentNodeIterator.getCollection(ContentNodeIterator.java:198)
at info.magnolia.cms.taglibs.ContentNodeIterator.doStartTag(ContentNodeIterator.java:262)

See attached patch for suggested fix, tested against a simple set of paragraphs but not against nested paragraphs.