Can't use Session.importXML with protected definitions

When trying to import (a jackrabbit 2.4.4 system export) I got this error

javax.jcr.nodetype.ConstraintViolationException: Unable to determine a valid node definition for the node "/importTestNode/b/rep:policy" in workspace "defaultWorkspace" of "My Repository"
at org.modeshape.jcr.AbstractJcrNode.validateChildNodeDefinition(AbstractJcrNode.java:1213)
at org.modeshape.jcr.AbstractJcrNode.addChildNode(AbstractJcrNode.java:1045)

When dealing with protected node definitions, it appears the code is doing a "return null" when it should be doing "continue".