Confirmed for 13w41b. I know that snapshot's outdated, but the fact that this is not a new bug deserves mentioning. Switched from my survival world (where I'm working on creating a "map board") to a creative superflat (where I happened to be experimenting with maps.) Brought out a map and it turned out to show part of the other world.
Edit: ...additionally confirmed in 1.7.1. Further experimentation shows that it does not actually overwrite any map data, but rather it appears to be re-using the maps from the previously loaded world. This happens when a map item in the second world has the same damage value as a map that exists in the first one - the game incorrectly loads and displays the map data for the previous world instead of the data for the current world.
Confirmed for 13w41b. I know that snapshot's outdated, but the fact that this is not a new bug deserves mentioning. Switched from my survival world (where I'm working on creating a "map board") to a creative superflat (where I happened to be experimenting with maps.) Brought out a map and it turned out to show part of the other world.
Edit: ...additionally confirmed in 1.7.1. Further experimentation shows that it does not actually overwrite any map data, but rather it appears to be re-using the maps from the previously loaded world. This happens when a map item in the second world has the same damage value as a map that exists in the first one - the game incorrectly loads and displays the map data for the previous world instead of the data for the current world.