Serverless iamRoleStatements Fn::Join in Resource

Serverless Framework
1

serverless.ts

iamRoleStatements: [
  {
    Effect: 'Allow',
    Action: ['s3:PutObject', 's3:GetObject', 's3:DeleteObject'],
    // using GetAtt
    Resource: '"Fn::Join" : [ "", [ { "Fn::GetAtt" : [ "s3Bucket", "Arn" ] } , "/*" ] ]',
   // using Ref
    Resource: '"Fn::Join" : [ "", [ "arn:aws:s3:::", { "Ref" : "s3Bucket" }, "/*" ] ]',
  },
],
  resources: {
Resources: {
  s3Bucket: { ... }

We are getting the next error. When I tried deploying the same policies using serverless.YAML it’s working fine
An error occurred: IamRoleLambdaExecution - Partition “” is not valid for resource “arn::Join” : [ “”, [ “arn:aws:s3:::”, { “Ref” : “s3Bucket” }, “/*” ] ]".

2 
    Resource: { 'Fn::Join': ['', [{ 'Fn::GetAtt': ['s3Bucket', 'Arn'] }, '/*']] },