Originally reported in https://github.com/localstack/localstack/issues/2099, the CreationTime for CF stacks was hardcoded. This was fixed in in LocalStack itself (https://github.com/localstack/localstack/pull/2103), but is now also fixed in moto (https://github.com/spulec/moto/pull/2818).

I don't know what version of moto you're using, and whether it's acceptable to use dev-releases, but if you do: 

moto 1.3.15.dev550 should fix this issue, so the LS fix can be removed if you upgrade :) 
'responseTemplates': 'ResponseTemplates'
            }
        }
    },
    'Kinesis::Stream': {
        'create': {
            'function': 'create_stream',
            'parameters': {
                'StreamName': 'Name',
                'ShardCount': 'ShardCount'
            },
            'defaults': {
                'ShardCount': 1
            }
        },
        'delete': {
            'function': 'delete_stream',
            'parameters': {
                'StreamName': 'PhysicalResourceId'
            }
        }
    },
    'StepFunctions::StateMachine': {
        'create': {
            'function': 'create_state_machine',
            'parameters': {
                'name': ['StateMachineName', PLACEHOLDER_RESOURCE_NAME],
                'definition': 'DefinitionString',
                'roleArn': lambda params, **kwargs: get_role_arn(params.get('RoleArn'), **kwargs)
            }