archetype:create-from-project generates xnl file, not xml

If you use archetype:create-from-project to create a new archetype from an existing project a file named "archetype.xnl" (note the n, instead of an m) is created in the directory "target/generated-sources/archetype/src/main/resources/archetype-resources/src/main/resources/META-INF".

This appears to cause archetype:generate to ignore the archetype-metadata.xml file.