CP8 - Issue with video player

Hi all,
I have to compose music for a video which is 3840x1080.
Quick Time player & KMPlayer are playing the video just fine but when I put the video in Cubase, no matter the format (I have tried mp4-h264 and avi), the video in the player is cropped (while at the project channel the preview works fine) and I only see the center of the video and not the left-right edges.
What is causing this issue? I didn’t have any problems like this in the past, but I haven’t tried this resolution again.
Thank you in advance for your responses.

Windows 7 (64-bit)
Cubase 8 Pro
AMD FX-6300
GTS 450

I’m having same problem with videos at 4k.

Did you work it out? Everything was playing nice at 1080p - converting to Apple Prores (proxy) now it’s cropped.