I recently ran into a case where GetResources would only render the resources returned by the previous call in the page. The resource I wanted to render did not have a parent, it's a document that the site admin can add to or leave out of a context. This code worked in a previous version of ModX 2.x:
[[!GetResources:default=`Check homepage for site hours!`? &resources=`[[findBy? ¶m=`pagetitle` &value=`Hours` &return=`id`]]` &limit=`1` &showunpublished=`1` &tpl=`Blank` &includeContent=`1`]]
To fix things I moved my Hours document to being a child of a doc called "Hours Parent". This works as intended:
[[!GetResources:default=`Check homepage for site hours!`? &parents=`[[findBy? ¶m=`pagetitle` &value=`Hours Parent` &return=`id`]]` &tpl=`Blank` &includeContent=`1` &includeTVs=`1` &processTVs=`1` &limit=`1`]]
I'm not sure what's going on, I suspect it's related to this bug:
http://bugs.modx.com/issues/5152