Typically BCI is CAD (additional CAD team if there is an in-house CAD team) for the users.
BCI will triage the problem, and if there is a tool issue, BCI will work directly with the vendor to help resolve it. Some customers prefer to work with the vendor directly after BCI has triaged the issue. We are open to either support model. BCI is not a competitor to EDA vendors so EDA vendors can work with us closely.
Currently, we are supporting one of our customers "as" their CAD team and directly talking to the vendor to resolve any issues.