I am experiencing the somewhat same issue here. I am not sure since when, but I cannot add any other members to my party. Is there any workaround?
Also, I`m not sure if this is related. But after the last patch, many maps I already visited seem so have been 'reset'. (Fog of war?) And I triggered some events (f.e. a scene in Dunnage, after rescuing Giacolo) where the relating characters are not even visible or at the scene.
Please tell me there is a way to fix my savegame :D