Some variables appear on RITM Form's variable editor but same does not happen with Catalog Task form. Following article will explain what are different ways to show variables on Catalog Task form.
There should only be two ways to get a Variable to show up in the Variable Editor on a Catalog Task form:
1.) Mark the Variable as Global
2.) Add it to the Catalog Task in the Workflow Editor from the list of available variables
However, if you have an available variable that is not marked as "Global" and is not added to the Selected list of variables in the Catalog Task Workflow Editor and the variable does not have a name ('empty' name). It will show up in the Catalog Task Variable Editor when created.