I think it depends on where you got the mod, at first I got my version from moddb (I deleted v3 beforehand). I received the bug that kicks you when you play as a specialist and doesn't allow you to play as cavalry. I looked into it and found another download link on forums here from gamefront. I deleted the old one and installed the one I got here, I noticed that I had to unzip this one before I installed it unlike the one from moddb. When I select cavalry I can play as them and when I select a specialist I don't get kicked, so I can assume that the way to play without being kicked is to download the one from the forums here.