Message id missing in onFinish callback passed to agent.stream

const stream = await agent.stream(messages, {
        maxSteps: options.maxSteps || 10,
        format: 'aisdk',
        runtimeContext: options.runtimeContext,
        modelSettings: {
          temperature: 0.2,
        },
        memory: {
          thread: threadId,
          resource: resourceId,
        },
        onFinish: async (step) => {
          console.log('these messages dont have ids :(', step.response.messages);
        },
      });