Phocus poor preview quality on DELL XPS 15

[ndscali]

I am experiencing very poor quality image previews (blurry) in Phocus 3.1.5 on my Dell XPS 15 (4k) laptop.
The fie looks like a low resolution version, very soft and blurry.
Viewing the same file on Phocus on my Macbook Pro shows it perfectly. Also when I view the file in ACR or Lightroom on the Dell XPS 15 the fie is fine.
I have checked all preview settings etc.
Has anyone experienced this problem and/or is there a fix for it?
Thanks
Nicky