As I said earlier in this thread, I am asking about how changes to recurring events propagate to (can be observed in) the child events. I observed that most changes propagate with no issue, but when I add a tag to the recurring event, it does not appear in the child events.
So on advice of angelo_NWL I deactivated the plugins and I found that adding a tag now propagates to the child events, but the booking that I created in one of the child events got dropped (is no longer there).
As I said above, it seems like this is something that can be improved, for example, by propagating only fields that change. In other words, if I change a tag field in a recurring event, then only the tag field of the child should change.