This bug still occurs. in MC 1.7 See https://mojang.atlassian.net/browse/MC-32436

Problem a map created in one world appears when you create a new world.

Here is a simple method to duplicate the bug in creative mode but it also happens in survival.

1. Create a new random world in creative, give yourself a map and view it, then exit and save.

2. Create a second new world and repeat the process. I expect to see the second world but instead I get the already rendered map from the first world.