User blog comment:DaNASCAT/Technical Update: August 19, 2014/@comment-452-20140819181031/@comment-5275700-20140825194910

@Bobogoobo, do the galleries with "undefined" entries also contain at least one link= parameter? Please send in details of any pages where you see navigation="true" being added to galleries with no existing link= parameter.

It's fine to remove navigation="true" from galleries that include useless links, but you should remove the useless links as well, or else the navigation parameter might be added back automatically in the future.