Interlace stripes in an upscaled progressive Video?

Hi,

I have been running Artemis with progressive option selected on a 1080p source video which is also progressive to bring it into 4K. While I have no interlace stripes on any single frame in the source video, a lot of frames in the upscaled 4K have these stripes, making it quite bumpy and uncomfortable to watch.

Any ideas what I might have done wrong with the settings?

This happens mostly when objects are moving, no issues with unmoving parts. Unfortunately I cannot attach any screenshots here.

Kind Regards!