Last modified: 2014-05-14 08:28:48 UTC
As of 3:24 UTC, https://www.mediawiki.org/wiki/Special:AbuseFilter/28 showed "Of the last 144 actions, this filter has matched 4 (2.78%).", but the hits were not logged. Either that line was wrong or, as I suspect, the filter hits are not being logged.
I peeked in the database, and didn't see any log entries for that filter. Flow calls \AbuseFilter::filterAction which in turn calls self::addLogEntries. Still investigating.
I can't reproduce this locally, logging is working fine.
This might have something to do with spamblacklist, as the entries added in https://www.mediawiki.org/w/index.php?title=MediaWiki%3ASpam-blacklist&diff=984908&oldid=961892 target this spambot. Possibly spamblacklist is the one actually blocking it, but then doing something funny (it also doesn't log its (apparent) flow hits in https://www.mediawiki.org/wiki/Special:Log/spamblacklist).
Now it shows 2 hits, which still doesn't answer the question of why, as of 7:55 UTC, it shows "Of the last 172 actions, this filter has matched 44 (25.58%). On average, its run time is 36.91 ms, and it consumes 70 conditions of the condition limit." Maybe it has something to do with caching?