here:
https://www.warmane.com/download there are 2 MoP clients:
1) " Mist of Pandaria" = MoP with WoD models. To run the game you need to use WoW_WoD_models.exe
2) " Mist of Pandaria (old)"= MoP standard, you need to run the game with WoW.exe as usual.
You DON'T need to install anything and since you get the first version it is "ok" that you have to use WoW_WoD_models.exe to play.
The "bug" about damage reduction does not matter with the Client you are using and I guess it is not even a bug.
However if you do not beleive me you can alwasy delete your MoP client a try to download "Mist of Pandaria (old)"