Directory has empty permission set in tarball created using fileSets with only fileMode defined

Using the following in an assembly descriptor results in a directory with permissions 0000 for the output directory rather than the default or existing which makes the directory unusable until the permissions are changed (the permissions on the file match what is specified in fileMode).
<fileSets>
<fileSet>
<directory>bin</directory>
<outputDirectory>bin</outputDirectory>
<fileMode>0755</fileMode>
</fileSet>
</fileSets>
Full reproduction project is attached. Note that this does not reproduce on 2.2-b5. This also does not reproduce if an explicit <directoryMode> tag is added.