I see what you mean. But there are two different things: the "active raid" mark that is placed on Cyclopedia's map when ANY announced raid happens, regardless of the subsarea it is located on; and the "upcoming raid" mark which is only placed on map if the character has completely explored the area on which the raid will happen. Since there are undiscoverable areas on the map, it is possible that an announced raid has no "upcoming raid" mark, even for players who have discovered all (discoverable) areas.