I work in an IOP program. Here it is customary for therapists and pdocs to not work with clients while they are in IOP. One major reason is that many insurances will not pay for clients to see both at the same time. It is seen as double dipping. Also if they are requiring a client to attend IOP as a condition of continuing treatment, they often express that the client is in an emotional place where they are feeling it is beyond their skill set. So they often avoid working with the client during that time so that the client will focus on the IOP program. This is not all therapists do this just what often happens.