ContextInterceptor: sessionId between two servers

I'm trying to use the Context Server Interceptor from the Docs: https://vertx.io/docs/vertx-grpc-netty/java/#_grpc_server
I'm surprised that the context seems to be shared among all calls. I was under the impression from the example (using a sessionId),
that the context is not shared between completely unrelated calls. How is this supposed to work?

### Version

4.5.11

### Reproducer

* https://github.com/andrm/vertxcontext

### Steps to reproduce

1. Run the server
2. Run the client
3. The client makes two calls, one to the context-intercepting server instance, the second to a plain grpc vertx service, no interceptor
4. The second call should not have the sessionId