Seems like a bug in your sandbox useImmer demo?

Not a big deal, but just as feedback - in the useImmer demo at 

https://codesandbox.io/p/sandbox/use-immer-bvd5v?file=%2Fsrc%2Findex.js

For me with both Chrome & FF, in the Preview pane, the `Tasks left` value seems to invert the selection of the first list item - "Learn React" - unchecked counts as "done", checked adds 1 to `Tasks left`

Just FYI