Hey Didier,
What type of upgrade did you complete? Was this an upgrade from a previous version of SmarterStats (say 8.x or below), or was this a minor upgrade from a previous version of 9.x?
Filter sets did change from 8.x to 9.x, and there could be a case where older data is not properly being displayed. If you could clarify the upgrade path I can confirm this is the case.
Thanks