No such problems on my phone. Not a single freeze or reboot since updating. However, I did hard reset and re-load after the update, so that may have helped. As others have suggested, it's probably something you have installed that's messed up.
I didn't really hard reset for any particular reason, just decided to "clean house" and thought the new update would be a good time/excuse to do it.
Oh, and Opera Mini 5 beta seems to support Kinetic, although I don't know it it's using the native OS or its own (like Skyfire).
The native browser sorta has it. If you do a quick swipe it will scroll very slightly past where you release. I suppose that could be what the post was referring to. But it's not full kinetic which should scroll much farther and faster. And nothing has changed since v40, it behaves the same as it did in v31/v21.