How can I resolve these banding or flickering problems before I shoot and in post FCP X?

Just back from two days shooting with my new Panasonic GH3. I tried some new settings turning down sharpness, color, noise ratio etc. Some shots had some really serious banding or flickering. The two examples are shot with artificial lightening 50 Hrz. frequency for Europe. I used the one point method (correct english name?) for measuring the available light. I don't understand it at all. Also because other shots under the same circumstances haven't got the same problems. Thank god I have enough shots to create the vid.

Anybody a clue why this occured? So I will be prepared next time. And is there a way to fix it in post with FCP X?

Because I'm still learning how to shoot with all the settings on my GH3 I set everything on automatic except the diaphragm - A modus. Other settings; MOV, 24 p - 50 Mbps (for Europe), Contrast -5, Sharpness -5, Color -3, Noise reduction -4.

Loading more stuff…

Hmm…it looks like things are taking a while to load. Try again?

Loading videos…