What did you shoot with? Is that the raw file and what did you playback with? Some programs aren't designed to playback intermediate codecs and therefore display fields out of sync, where if you played it in a program that understands the codec, it will display it fine.
EDIT: Realized this was in the GH2 section, question still applies about what formats you used.
On a PC, avisynth can be used to reconstruct progressive frames from the AB BC CD DE sequence, but on FCP I have no idea sorry. Deinterlacing may be your best option, although you will lose some resolution.