User directory fails to load users on a subwiki when mixing skins between colibri and flamingo

To reproduce:

• create a subwiki on a standard 6.4.8, with only global users available
• put some users as members of this wiki
• go to user directory, you'll see the users in the user directory
• set the skin of this wiki to "colibri"
• reload user directory, it will not display any entry anymore (see screenshot)

The result of the livetable results page for the user directory is this:

#gridresultwithfilter('XWiki.XWikiUsers' $request.collist.split(','), "$!extraFromClause", "$!extraWhereClause", $extraWhereClauseParameters)

A couple of notes:

• it's important that global users are available in the wiki. If the wiki has local users, the issue will not reproduce
• the issue also reproduces also if, at step 4, the skin of the main wiki is set to colibri (or some skin that inherits from colibri) and the skin of subwiki stays on flamingo. It just has to be different between the subwiki and main wiki.
• If, at the end of the URL that obtains the livetable results for the users livetable, a parameter skin=sdfjgs is added, the results will work and display properly. It doesn't matter what is the value of the skin parameter