It seems that on sites where you don't have the access review queues privilege, you don't see the results of reviews in the timeline. Example:
However, you are able to click on the review itself to see the results, so it makes no sense to hide it. Even if it did, it's not really consistent: on sites where you have access to First questions but not e.g. Suggested edits, you still see the results for Suggested edits in the timeline.