Thank you for your reply. So here is the workflow:
The footage has been recorded on BlackMagic HyperDeck Studio recorder in 185 DNxHD 50i OP ATOM MXF, upper field first.
It has then been imported into Avid Media Composer via media browser (basically I just had to copy the files into avid folder and drag them into bin with media browser, because it had already been Avid’s codec).
After the editing I exported the AAF to Davinci, where the problem occurs within the program.
After the grade I exported OP ATOM (same as source options) back to Avid where I also exported same as source, adding some titles. I also tried exporting ungraded version. As it turned out as I checked it on the interlaced monitor and hardware, the ungraded version was playing fine, while the graded version had those “fades” between cuts.
When exporting I always used setting that were same as source.