Ray IDEL high load

ray version == 2.8.0, python == 3.10
I stop pushing tasks, and after all tasks done, the worker node’s cpu load is still high…
I try to check the log of worker.

Can anyone tell me how to next try to locate this problem?
In process of IDLE, there are lots of my task which should done, but still run.

And btw the other issue, there are still 10 core cpu not release…I don’t know why.