I have the same issue here. It happens with all the terminal python process and also those started by pycharm. In the Terminal I'm running saltstack master, minion and api process that spawn other python process so for those I'm getting around 14 process in my dock. Just upgrade yesterday Sept 22 and before the upgrade wasn't an issue

Sorry but this answer doesn't solve any problem at all It's just a way to diminish what it's really happening with the dock that right now it's not usable at all This it's not something that we as users are doing new now. It's something that started to happen with the upgrade to Sequoia. In my case with completely server process that uses no GUI at all and also aren't been running as a service, I manually run it in my terminal. Hope for a new MacOs update that fix this issue

Try running this on the terminal: killall Dock