The ocgrpc plugin inserts the "method" key during tag propagation. I found this in real life usage and I had to manually get around this with
https://github.com/orijtech/opencensus-experiments/blob/0ac9edcefcf4273c0d4f6dfa85a53cfc8e527f66/integration/go-grpc-client/interop_test.go#L103

and @Ramonza encouraged me to file an issue

This is where we insert it