be sure that if you have ACE Medical loaded, that the "revive" option is disabled (which is default), and if you are using ACE Advanced Fatigue, that "stamina" is enabled (which is default). prior to generating a mission, after the role selection and mission start, you can reset DRO options to their default values as well.

Whenever Im starting the mission on ground, my AI squadmates are stuck. They move and listen to stuff but they are like stuck slightly above ground and can't move.