[user104658]

Her "illness" was probably down to the stress / anxiety of the whole situation. She seems robotic because she plays her cards close to her chest but, if anything, that can just make it build up more. She probably was feeling "unwell" with it but definitely never intended to return.

I also suspect that her and Steven must have discussed it. Either deliberately unshown by BB, or they've been having sneaky whispering sessions off-mic under the covers. He definitely knew she was going, anyway.