Tracking categories does not always sort pages according to their DEFAULTSORT value.

For example pages are sorted by pagename in [[Category:Pages with script errors]] if an error is invoked before DEFAULTSORT in wiki code:

{{#invoke: some error}}
{{DEFAULTSORT:not page name}}

But pages with an error after DEFAULTSORT are sorted by defaultsort value:

{{DEFAULTSORT:not page name}}
{{#invoke: some error}}

When categories are added by usual wiki category syntax ([[Category:...]]), the defaultsort value is used regardless if DEFAULTSORT is before or after the category. I think it should be the same for tracking categories.