I usually pass the review tests. (In fact I can't remember the last time I failed.) But I wonder what's going on to someone who repeatedly fails to pass these tests?
If one fails too many reviews (in a relative sense) then one will be banned from reviewing for some time. Failing them only rarely is inconsequential, and it is generally acknowledges that even a careful reviewer can fail some (due to such decisions sometimes being inherently subjective).
For some more details you can see the respective FAQ on MSE What are review tests (audits) and how do they work? I believe the precise thresholds are not documented though.