Python interpreters don't terminate automatically in MacOS Follow

Hi,

My pycharm doesn't automatically terminate python process after running.

After running test for a few times, there are a lot of python process under the background. 

Therefore, my CPU usage and memory become very high, and my computer becomes very slow.

I've used pycharm for a long time, and never happen this situation. Does anyone know how to fix it?

Thanks.

p.s. pycharm version is community 2020.3

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[Update]

I downgrade my python version from 3.9 to 3.8, then this issue has been fixed. The pycharm would terminate python process as usual.