After playing around with this quite a bit, it seems to be an issue only in the Simulator. Try running the app on your iPhone. That worked for me. After a couple of seconds, the data updated with the new item. This was the case in two different apps I'm working on.

It's been 4 months and I still have this issue. Any workarounds?

Where should this code be added in order to kill the Live Activity when the app is closed?

I'm getting the same error. Did you ever figure this out?