I’ve noted last versions of Nomachine (maybe the 4.36x series) put a kworker process to high CPU utilization, making almost unusable the remote physical desktop
For the moment for this release, there have been no changes that may affect CPU usage for quite a while, so I don’t think it’s directly related to changes to the NoMachine software. It seems more connected to a change to the Linux system. This kworker processes are started by the kernel for various reasons, for example to handle I/O or interrupts, except that there is no new I/O or interrupt compared to the software released 1 or 2 months ago.
Please send the output of the top command taken while somebody is connected to the physical desktop and while the NoMachine system is idle. Take the same output using top -H (this will show the threads one by one). Include the exact version of the Linux kernel you are using (so we can possibly try to reproduce it), the exact version of the NoMachine software and, if possible, the logs on the server (check here how to get them: https://www.nomachine.com/AR07K00677). If there is any thread entering a loop eating CPU it should be easy to find out which one it is from top and the logs.