External key output on UltraStudio HD mini at 3G framerates

Hi
I am having issue getting a sensible key out from a UltraStudio HD Mini at frame rates of 1080p50 and above. I just vertical white lines. A post a year ago looks like someone else had a similar problem on a UltraStudio 4K unit, and the latest drivers fixed it.
I am using the latest drivers, 10.9.7. The software is Ross XPression v7, although I get a similar result using Media Express and using LiveKey to put the unit into External key mode.

Thanks
Simon

It was suggested by Ross Video to remove the LCD screen, as that has been an issue, but it made no difference here.
Here is a picture of how it looks. This is the key output, with the fill at black.

Picture showing key output at 1080p60. The fill is black at this point.

20171218_152357262_iOS.jpg (970.46 KiB) Viewed 1423 times

Any ideas please?
Thanks
Simon

I know this is old, but I am having the exact same issue. Did you ever find a solution?
My alpha key is looking really grey and washed out and also has those vertical lines you described. The key works perfectly at 1080 25p, but goes all funny at 50p.

I'm running the latest version of LiveKey, running png assets out of Qlab 4 on a MacBook Pro 2018 with an Ultrastudio 4K.

I'm having the same issue, any solution?

Well, the problem is partially solved. The Ultrastudio works perfect in other applications but I only tested it with Blackmagic Media Express which doesn't work.