Coincidentally I filed a bug report about this tonight.
When you cut/copy strings with special characters from within the game, they lose their encoding.
1. You can copy special characters from outside the game and paste them in -- they display fine.
2. You can type special characters directly into the game (for example, using Windows codes such as Alt-0151) -- these will display fine.
3. If you copy special characters from within the game to paste elsewhere -- either in the game or outside the game -- the character encoding will be incorrect. Something is switching the encoding from Unicode (UTF-16 most likely) to what is probably ANSI.
This can be reproduced game-wide; it's not just in the MA system. For example, paste into the chat box, highlight it in the game, copy it in the game, and paste it back into the chat box -- it will be broken.