what is this? Apple Prores error? Encoding problem ?

We recorded the video feed in Apple Prores HD. During recording ( and live switching ) none of these phenomenon were visible. After viewing file in quicktime before editing... or after viewing FCP export in quicktime... it's visible.

We use three cams that are set to 1080i50

2x Sony pmw 350

1x Sony Ex1

Videofeeds are fed to Black Magic Design ATEM switcher. TVS.

2x BM ATEM TVS sends feed to livestream encoder and to Atomos Ninja 2 and Atomos Samurai recorder, recording in Apple Prores HQ. ( all switchers and recorders are tested with several versions of software ). Also on playback on the Atomos recorders the problem is there... so the problem is not caused by mac or FCP.

The HDD's with the recordings are transfered to a few relative new Apple iMac's with FCP.

I've also a movie posted with example https://vimeo.com/58436983/ and another pic:

When connecting the two recorders to one source switcher... this phenomenon appears in both recordings...at exactely the same time.....

So it is something posibly origination by camera or switcher.. and "translated" during encoding to apple prores to this? Does this make sense?

So far i can see, this problem only occurs when connecting professional camera's instead of semi pro cams. ( we usally only use sony ex1 or ex1r cams.. and face no problems ) Is this posible, do these bigger / profesionall camera's make other use of the signal?

I have allready placed same like questions tot Black Magic Design and Atomos. but they are still looking..... hope anyone here knows this " error "

BR

Sander