Process owned by a user remains active after the user logs out

Question

I share my MacBook Air¹ with my son. When he is logged out² of his user account and I look at the activity monitor in my account, there are several processes owned by his user that are still running:

When I took the screenshot³, the processes were all at 0% CPU, but I noticed them because com.apple.geod briefly rose to the top with around 5% or 10% CPU.

In fact, I only startet up the activity monitor to check whether another process owned by my son was active again. He is playing Fortnite on this MacBook and a few days ago, after he had logged out and I had started using the computer, the cooling fan became very noisy, so I checked the activity monitor and saw that a process called EpicWebHelper owned by his account used a lot of CPU, until I killed it. I edited the launchd plist for that process to keep it from starting every time the computer was turned on. I guess it's nice for my son to have his game running when he logs in, but what I don't understand is:

Why does a process owned by a specific user remain active when the user logs out?

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Notes.

1. MacBook Air, mid 2012, macOS 10.15.7
2. My son logs out via the Apple menu.
3. All the processes shown in the screenshot are owned by my son's user account. I just cropped his username to protect his privacy.

Answer 1

macOS is technically a multi-user system, there is nothing „wrong“ with having processes running which are owned by users not currently logged in. The processes you list seem to be usual things, don‘t see anything malicious.

PS: Of course sometimes things just get stuck due to bugs :-)