I've delved deep into the map systems and found that, although it is poorly coded, there is something I cannot comprehend.
It... somehow uses a symbol that the World Editor does not accept (The '$' sign, which is used in other languages though).
My initial thought was just to retrieve the code, add it in the world editor and examine it. But when I removed the line with the weird symbol in, the system would change the camera, but not the minimap.
Strangely, that symbol is used for a unit command. I wouldn't know why a unit command would mess up the code like that.
Maybe it's just my editor not willing to accept the code...
Either way, so I found out that the script (although literally copied and left completely unchanged - aside from commenting out that one line with $ in it) failed.
I checked for imported files, seeing if there might be anything added to the map that could cause this... strange behavior.
Again, this is a dead end for me. The standard Warcraft files (war3map.[extension]) are either unreadable or do not provide enough information, and amongst the other files are only images and models. No scripts (and I did check for minimap models/images as well, with no luck).
I may talk to some other people about this. See what they know.
Or, if you by any chance know the author of the map (or know how to reach him), you could ask it himself.