The filter for getting questions from all meta sites seems broken, every time I try to use it the resulting list of questions is emtpy. [Here is one example filter][1] for getting all questions tagged [tag:discussion] on all meta sites, it does not return any questions for me. If I change "All Meta Sites" into "All Sites" it returns questions as expected.

This used to work some days ago and suddenly stopped working.


  [1]: http://stackexchange.com/filters/19036/my-filter-3