Just found an odd problem -- not sure if it's something I did or if it's just screwed up in general though.
Noticed that a scap was recently done on Wikimedia and so went to try out Special:Blockip to find that the "Prevent user from sending e-mail" message (MediaWiki:Ipblockemail) displayed as <ipblockemail> (or whatever screwiness it is when there is no such message), although the message had been defined in MessagesEn.php. When I went to the system message, it displayed the correct default message but did not take effect until I saved the message (creating it with its default value). This problem does not seem to exist on testwiki, and it never did on my local wiki or my public testwiki. Any idea what's going on?