I can confirm too! Fixed! :)

I've just received answer from Atomos that it is GH5s output issue. But I still didnt get any answer from Panasonic. 

On 4/4/2018 at 9:37 AM, pkiener said:

I got this from the Atomos support team:

looks like it's a issue on Panasonic side. We are working on that.

And then:

Our engineering team is aware of this issue. They are working on this. Not sure where is exactly the issue.

So we will have to wait...

I have received same answer from Atomos support but still waiting for final answer. Panasonic did not answered anything. That is strange. And after all testing I am pretty sure that issue is on Panasonic side.

I had GH5 and its capable to output UHD 60fps 10bit HDMI. Approved! GH5S specs say that it is capable for DCI 4k 60fps 10bit HDMI but reality says different. I just wanna know is this general issue or not. And want to know from Panasonic is that a hw limit or it will be fixed with future firmware upgrade.

Has anyone noticed stuttering/chopping issue when GH5S output DCI 4k 60fps 10bit signal to Ninja Inferno (I am using Atomos HDMI 2.0 cable)? Stuttering is visible on both displays even without recording. It looks like camera can not handle with those settings. I have tried another settings and every other settings works ok. 

DCI 4k 60fps 8bit HDMI output works OK.

DCI 4k 30fps 10bit HDMI output works OK.

UHD 4k 60fps 10bit HDMI output works OK.

I have contacted Panasonic and Atomos but still did not get any answer.

Video sample DCI 4k 60fps 10bit HDMI output

https://drive.google.com/file/d/1O0mQDdoDQy48yVMz8z7Msd09gxkDlDph/view?usp=drivesdk

https://www.youtube.com/watch?v=GovMGFzg0hw

Nikon D5: 4K UHD Video - My Nebraska

https://www.youtube.com/watch?v=GovMGFzg0hw

Nikon D5: 4K UHD Video - My Nebraska