I'm guessing you just added modded characters. If that's the case you have to delete the files in the Saves folder. Yes, and start over.
Fresh install, no mods, I've tried on other versions and the same happened. Figured it was a bug but didn't think anything about it, but I'm missin out on xcom combat mixed with big tums. A travesty truly!
edit : tried adding the example mod into the mod folder for funsies, and nothing new. the only things that work are the quit and the settings, the latter of which won't close after hitting return.