What makes you think it is a NoMachine bug?
It looks like Xorg process is pegged at 93+% CPU.
Not only that. I see nxnode.bin at 0.7% and nothing else running. I suggest you send an email to the CentOS people or Red Hat. I’d tend to exclude it’s NoMachine.
For the record: it seems that you are running a “remote desktop” session, not even a “virtual desktop”. So your KDE desktop runs in Xorg, not in nxnode. In other words X clients are connected to Xorg. What NoMachine does for “remote desktops” is just querying the content of the top-level windows on a interval (in your case, probably 25 times a second). I have never seen a Xorg instance taking more than 5% of the CPU to return 25 XShmGetImage() per second, even on HW of 10 years ago (that we keep here for testing). Even if you had disabled the X-SHM extension in Xorg.conf (that would have been deliberate), load should have distributed 50%-50% between Xorg and nxnode. Yes, it looks like a Xorg or KDE bug. I’ve also seen Pulseaudio causing this kind of behavior. I hope for you it can be solved with an upgrade.