In the C1 Console's XSLT editor you can use the debug fields (on the Settings tab) to simulate a specific page - if you set this to one of the sibling pages which present a problem and then do a preview - do you then get the data you need or not?
If you do not get the needed data, you should look at the filter applied to the GetSideLinkXml function call. Probably you are filtering on "current page". This should be changed to "current and ancestors".
