...when different identity states convey contradictory information and then have amnesia for what the other identity states said, the patient may be thought to be lying. This can appear to be characterological mendacity when it is not.
Elizabeth F. Howell, Understanding and Treating Dissociative Identity Disorder: A Relational Approach
alter-personalities, dissociative-identity-disorder, faking, liar, lying, mental-illness, misdiagnosis, pathological-liar, stigma