Dropped frames using paired 32GB SD cards

I just filmed a performance using my pair of Panasonic AC-Ag90 cams. They both held two 32GB SC cards, recording AVCHD on both simultaneously. A Canon was also used that outputs .MXF.

I converted the .MTS to .MOV from the 2 panasonics first in Movavi. I quck reviewed them in Real Player and did not notice any skipping. But, when I imported and started editing, the dropped frames, pixelated images were severe. Sound was ok. I then converted MTS and MXF files into .mov using Wondershare video converter. (I needed all files to be .MOV since I was also using a Canon that output in .MXF.)

THE PROBLEM IS: all .MTS footage has skipped and dropped frames, pixelated images throughout all 4 chips (2 chips per Panasonic camera) The Canon footage is ok.

Why?

1) pre-used SD cards that were erased using Disk Utility? It seems odd that all 4 chips would drop.

2) one or both of the Converter programs? odd that both conversion programs would create dropped frames.

3) the Panasonic cams . . again, odd that BOTH cams would suddenly start doing this.

I am editing using PPCS5 on iMac, 3.5 GHz Intel Core i7, 16 gb ram, NVDIA GeForce GTX 780m 4096 mb, on 10.9.2.

Thank you for all and any suggestions?

Jana