We've noticed that FlaggedRevs on pl.wikipedia sometimes doesn't autopromote users which appear to be eligible for it.
Looking through the rules available at , this user appears eligible for autopromotion (I manually checked, he fulfills all listed conditions) - however, he still wasn't promoted to the 'reviewer' status.
This is somewhat rare, but it did happen at least a few times (sorry, but currently I don't have any more examples at hand). I think in most cases the user was granted the right manually, by an administrator passing by.
(I didn't know whether to report this under Extensions/Flaggedrevs or under Wikimedia; I eventually chose the former.)
 https://noc.wikimedia.org/conf/highlight.php?file=flaggedrevs.php , grep for 'plwiki'