I had a similar issue when I upgraded except that ALL my gestures worked perfect except the two finger swipe in Safari. Tried every possible combination, reset all the gestures, re-installed Safari, etc., etc.
Can you create a new user/login and replicate the issue? When I created a new user/login it worked perfectly fine so figured it was a preference file glitch in my main user account.
Find your .globalpref file (which is a hidden file) in your User Library and replace it with the .globalpref file from the user that it is working in. Worked for me! It will clear some of your general comp settings, but also resets the trackpad.