Tama yata si sir Quitacet.
Brightness pops ended with the D series plasma. Wala pa akong nabalitaan na brightness pops sa E, F and H (no such thing as a G series sa Sammy plasma), na similar sa D series na walang workaround at walang fix. The D series was issued a firmware fix, but users say it either didn't work, or only worked temporarily.
Ang alam ko lang na brightness pops ngayon ay minor na lang na merong workaround. Even my 51F8500 has it --- on 3D mode, 24p source, using Cinema Smooth.
Try it on your 64F8500: The first scenes of Prometheus 3D, using a 60p frame rate --- obvious brightness pops. Set 24p frame rate on the player, and Cinema Smooth Setting on the TV, the pops go away. Or disable Cinema Smooth on the TV, the pops go away.
Note: there's a bug on all F8500 TVs. Disabling Cinema Smooth automatically enables Motion Judder Canceller (MJC), even if it is off. To correctly disable MJC, you must turn MJC off even if it's already off.