gql: Websockets transport stuck during the close step of a connection

I am using the gql from master and experiencing an occasional deadlock. The library I’m using is calling client.execute() with a websocket transport. Sometimes I see an error like this: Exception in subscribe: GeneratorExit() and then client.execute() never returns.

WebSocketTransport.execute() does return an ExecutionResult, i.e. first_result is set. Also AsyncClientSession.execute() returns.

Maybe it’s failing to close the connection?