I'm very wary of making such diagnostic judgements on anyone without knowing them, never mind on the basis of something as artificial as a TV interview in the run-up to a general election.
The Sky clip here certainly confirms that she's poor at such interviews - not great at thinking fast on her feet, and prone to looking and sounding evasive without actually succeeding in evading anything. But I'm not sure I'd even speculate that there's something (other than what I've already said) 'wrong with' her on the basis of it.