When RC patrol is used concomitantly with FlaggedRevs (e.g. in its protection version), both the review interface and RC patrol interface appear on reviewable diffs. See background.
Since reviewing has for effect to mark the reviewed revisions patrolled, I think we should not show the RC patrol UI since it is still present after the review even though they have been patrolled already (users might think they weren't patrolled, and do it for nothing).
In core, we could ask extensions with the DiffViewHeader hook.