Hi Henrik, had the same problem. Seems that sometimes PP cant detect what fieldorder your clips are.
I solved my problem by manually “modify the footage” and click on the correct fieldorder (in my case upper field).
The “stripes” you are seeing is because the material is interlaced. Nothing is wrong. But if you are going to use your product mainly for viewing on computerscreens, you better make your export “progressive”.
Difference beween interlaced and progressive is explained here : https://en.wikipedia.org/wiki/Interlaced_video