We had some lag on English Wikipedia’s [[Wikipedia:Special:Contributions|Special:Contributions]] and [[Wikipedia:Special:Watchlist|Special:Watchlist]] for a few hours today; the new database server handling that crashed for a bit and, though it came back up, its replication configuration was slightly corrupted. Domas was able to quickly fix that once we were alerted, and it should be caught up soon (currently running less than an hour behind).
Currently our replication lag detection only seems to work properly when replication is running — looks like we need some work on cases where replication is off entirely!