Our product documentation states that the TLS Termination and HTTP2 policies must be in place and correctly configured for gRPC traffic to pass through the APICast Gateway.

What steps beyond testing HTTP2 functionality can be done to confirm gRPC traffic is set correctly for APICast?

We have a customer issue where they wish to use APICast with a gRPC backend hosted in Service Mesh:
TLS Termination and HTTP2 policies are in place and configured.
HTTP2 traffic through APICast to the backend works
gRPC and HTTP2 traffic work directly from the APICast pod to the backend
There is no indication in the APICast logs that gRPC traffic is being accepted.