Optical Flow and Vector Motion Blur seems to be broken ((
When I use Optical Flow and Vector Motion Blur, every time i got this artefact line in the bottom of screen. With DR 16,17 or Fusion Studio 16,17 result the same 
https://forum.blackmagicdesign.com/
https://forum.blackmagicdesign.com/viewtopic.php?f=21&t=132945
Jim Simon wrote:Steps to reproduce?
Mario Kalogjera wrote:Confirmed. Not there in standalone Fusion 9.0.2.
Can't be bothered to install Fusion 16...sorry...