Nested repeated params with ScalaForms play 2.6

I learnt from here that Play has support for nested repeated values. But actually it's not loading the values in case class attached with Form validation object.

case class CourseForm(title: String,
                      description: String,
                      fees:Money,
                      tags: String,
                      syllabus: Seq[CourseSyllabusTopic])

class CourseController @Inject()(cc: CourseControllerComponents)(implicit ec: ExecutionContext)
  extends CourseBaseController(cc) {

  private val courseForm: Form[CourseForm] = Form(
    mapping(
      "title" -> nonEmptyText(minLength = 30, maxLength = 256),
      "description" -> nonEmptyText(minLength = 140, maxLength = 2048),
      "fees" -> mapping(
                        "amount" -> number(min = 0),
                        "currency" -> nonEmptyText(minLength = 3, maxLength = 3)
                )(Money.apply)(Money.unapply),
      "tags" -> nonEmptyText,
      "syllabus" -> seq(
                        mapping("title" -> nonEmptyText,
                                "description" -> nonEmptyText
                        )(CourseSyllabusTopic.apply)(CourseSyllabusTopic.unapply)
                )
    )(CourseForm.apply)(CourseForm.unapply)
  )
......}

And here is the RAW Post data of HTTP request I am making. From last two hours I have tried every possible way, but I was not lucky enough.

title:Crash course on Ins and Outs of all major crypto currencies and tokens, and block-chain technology.
description:Crash course on Ins and Outs of all major crypto currencies from bitcoin to etherium to altcoins. We learn about all the terms and technologies used in this emerging new field of crypto-curremcies
fees.amount:50
fees.currency:USD
tags:introduction,block-chain,crypto-currency,bitcoinq
syllabus[][title]:Introduction
syllabus[][description]:In this topic we will start from very starting by exploring different breakthroughs before our current block-chain based currencies arrived.
syllabus[][title]:Introduction2
syllabus[][description]:2 In this topic we will start from very starting by exploring different breakthroughs before our current block-chain based currencies arrived.

And on backend when I print the Form object/instance I get the following result with List being empty.

CourseForm(Crash course on Ins and Outs of all major crypto currencies and tokens, and block-chain technology.,Crash course on Ins and Outs of all major crypto currencies from bitcoin to etherium to altcoins. We learn about all the terms and technologies used in this emerging new field of crypto-curremcies,Money(50,USD),introduction,block-chain,crypto-currency,bitcoinq,List())

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