WorkflowClient#execute doesn't pair correctly with workflowStub.getResult()

Actual behavior

https://github.com/Spikhalskiy/java-sdk/commit/40c0d626e0ea4778a956e388d33754e67bde23a8#diff-7cfba47d2337ff3ee746b09a4d916e5e839f9b8bff45a26e588727667437c160R94

  @Test
  public void executeAndGetResultFromStub() throws InterruptedException, ExecutionException {
    TestNoArgsWorkflowProc stubP =
        testWorkflowRule.newWorkflowStubTimeoutOptions(TestNoArgsWorkflowProc.class);
    WorkflowStub workflowStub = WorkflowStub.fromTyped(stubP);
    CompletableFuture<Void> executeCF = WorkflowClient.execute(stubP::proc);

    // This test hangs (times out), but uncommenting of either if these two lines makes it
    // pass, which doesn't make much sense
    // sleep(1000);
    // executeCF.get();
    workflowStub.getResult(Void.class);
  }

This unit test for a trivial workflow, that finishes immediately, hangs.
Uncommenting on either sleep or waiting for a completable future makes it pass.
Replacing execute with start (that returns WorkflowExecution) also makes this test pass.

Expected behavior

The test passes.