A claimant of Incapacity Benefit applies for Carers Allowance (meets criteria) should be paid via underlying entitlement rules - will they be automatically requested to attend an interview at job centre and what can they expect to happen at the interview?

Around here they are virtually automatically called for the double interview i.e. checking the form and the work focussed part although they may have passed a personal capability board with no recall for several years.
Sometimes the work focussed part is waivered because a clear case can be made why a claimant would not be able to look at return to work activities. E.g. both partners are ill, or there is a disabled child for whom both need to care as the child has very challenging behaviour

2 points you probably also come across 1.at medical board possibly also during pathways series of interviews the claimant is asked about the caring reponsibilities, especially if they are incapacitated with mental health problems.

2. Caring for some one else but the list of the close relatives
is not exempt work under the incapacity rules e.g. friends or same sex couples even if they live at the same address. Sometimes this is not acted upon by the decision makers for a long time. And is also not picked up at the interviews