Yeah... mediawiki 1.19 started "caching" messages in the database (in addition to all the other places where messages are cached!)  This was never a problem for us until VisualEditor, which uses resource loader, which causes the messages for VE to be cached.  None of our normal cache clearing methods actually clear this cache, so every time VE team was changing messages, we had to delete these rows from the database.  Since we don't care about that feature, we just removed it.