Not only Ranking Filters on Ranking tab, this happen also on filters within the Robustness tests. When you change one of these values, and then inmediately you restart SQX. Then the values that you modified aren't changed. This happened to me all the time, and some users I've been taking to.
Even without reboot , I have come across a bug on the ranking parameters where when you change parameters in one task in a workflow all the ranking parameters get changed in all tasks