Localstack error in Step function with DefinitionS3Location - aws-cloudformation

Question

I am trying to deploy a lambda and a step function in localstack. I keep my step-function-definition in s3.
The cloudformation documentation says we can use DefinitionS3Location instead of using Definition or DefinitionString.
This is what I am doing.
template.yml:
# Lambda function
EndToEndTestLambdaFunction:
Type: "AWS::Serverless::Function"
Properties:
Handler: index.handler
Timeout: 30
Runtime: nodejs14.x
MemorySize: 1024
PackageType: Zip
CodeUri: s3://step-lambda-zip-artifacts/index.zip
Role: !GetAtt IAMRole.Arn
# Step function
EndToEndTestStepFunction:
Type: "AWS::StepFunctions::StateMachine"
Properties:
DefinitionS3Location:
Bucket: step-lambda-zip-artifacts
Key: endToEndTestRunner.json
DefinitionSubstitutions:
EndToEndTestLambdaFunctionArn: !GetAtt EndToEndTestLambdaFunction.Arn
RoleArn: !GetAtt IAMRole.Arn
docker-compose.yml
version: "3"
services:
localstack:
image: localstack/localstack:0.12.15
container_name: localstack_fundle
# restart: always
ports:
- "4566:4566"
environment:
- SERVICES=iam, lambda, dynamodb, apigateway, s3, sns, cloudwatch, ssm, stepfunctions, sqs, cloudformation
- DEBUG=1
- DATA_DIR=/tmp/localstack/data
- LAMBDA_EXECUTOR=docker-reuse
- DOCKER_HOST=unix:///var/run/docker.sock
- DEFAULT_REGION=eu-west-2
- STEPFUNCTIONS_LAMBDA_ENDPOINT=http://localhost:4566
volumes:
- my-datavolume:/tmp/localstack
- /var/run/docker.sock:/var/run/docker.sock
volumes:
my-datavolume:
As per the cloudformation doc, the definition is optional and I am using the s3 location for the definition. But each time I try to deploy I get the error:
DEBUG:localstack.utils.cloudformation.template_deployer: Error applying changes for CloudFormation stack "development-localstack-Test": Parameter validation failed:
| Missing required parameter in input: "definition"
It's weird because it does not go with the doc!
At first I had the impression that the problem is from the cloudformation but it is not. Found a localstack issue about this but no solution over there.
Is this actually a localstack issue and is there a way to make this work?