Npc tilesets are set in a way in that they all have specific slots in the Map Properties. If I'm not wrong, NpcRed is set the second slot. You can actually change this by going into the Npc.tbl editor and going to the entities of the tileset (Like the Red Bat, Red Critter etc...). It shows that they draw from a certain slot in the Map Npc Tilesets, and you can easily change that to the first or second slot. If that's not the problem, I'm not quite sure, you could try saving from the CE main screen. (I'm pretty cure you're using Cave Editor)