Have been using this machine for a good number of years (10?) and more and more I have had water flowing around the filter. Have been replacing the gasket regularly and just did so about 2 months ago. Have been tightening it very hard. However, it now seems I get water flowing around the portafilter with very little (almost no) tamping. Worse with finer grind but seems the problem is fairly regular.

Not sure it is the gasket area problem....can the filter holder or portafilter itself get distorted to a point where a new gasket does not resolve the problem?