Still a problem for me, x2goagent showing constant high CPU usage with macOS client and Ubuntu 18.04 server:

 

x2goclient running on macOS 10.14.3

X2Go Client v. 4.1.2.1 (Qt - 4.8.7)

 

x2goserver package 4.1.0.3-0~1708~ubuntu18.04.1 on Ubuntu 18.04

 

If I connect to the same Ubuntu system from a Ubuntu client x2goagent does not show high CPU usage.