@eieio How quickly does our activity sync with the server?

I notice that when I check an empty box it is often instantly cleared.

Unchecking a box, or undoing the efforts of another is a different thought process from checking a box that was empty.

So in this case, I am wondering if the person who cleared my checkbox meant to undo my work or if they were themselves attempting to fill an empty box and the timing between us caused them to clear "my" check instead. And vice versa.