diffDatabaseToChangeLog creates invalid xml files

While comparing two databses (mysql) the xml file created is invalid.

<changeSet author="xxx (generated)" id="1400232139845-48">
<dropIndex tableName="table"/>
</changeSet>

indexName is missing...

The index should not be dropped at all, the next line in that xml is the following:

<changeSet author="xxx (generated)" id="1400232139845-49">
<createIndex indexName="PRIMARY" tableName="table">
<column name="id"/>
</createIndex>

What should be dropped is the Foreign Key, see screenshots.

This bug was not present in 2.0.5, but seems to be there in all 3.x.x versions