Krasnogorsk K3 — 16mm film scan — Lines not scratches?

[Knopfloch]

Hi all,
I just received the digital files back from a test roll of 16mm film shot on a Super 16 modified K3.
Overall I'm happy with the quality of the scan.
BUT there are a couple of lines running through the center of the frame which don't appear to be scratches.
Have a look here:
https://vimeo.com/193331897

I'm not familiar with the technology of this camera but assume that the light is not hitting the film directly through the lens but is reflected over some mirror system?
This might be the source of the problem with the mirror being scratched?

Any advice here would be great.

Also each new shot starts with a wonky focus shift in the top left corner. Is this due to the brutal mechanism of this camera and the abrupt start of the transportation, causing a short vibration? Is this a general problem in cameras like this?

Thanks for your help.

Markus