Hello @anon56468539 and welcome to the community!
Thank you for your report. This is very important feedback, difficult to investigate though.
First of all I can refer to related community thread. 3.4.1 is the new version that contain some fixes for issues discussed in this thread.
If you are ready to help in investigation, I would suggest to check if you have any orphaned processes. Since you are using new v3.4.1 you shouldn’t, but still.
And also thread dump made when you have 100% of CPU usage would be useful.