Issues with value and saveInto parameter in a!checkboxfield()

a!localVariables(
  local!question: split(rule!MWJ_qe_multiCorrect_fetchQuestion(), ";"),
  local!option: split(rule!MWJ_qe_multipleCorect_options(), ";"),
  local!numberOfAnswers: 4,
  local!correctAnswer: rule!MWJ_qe_MultiCorrect_CorrectAnswer(),
  local!selectedAnswer: rule!MWJ_QE_MultiCorrectOption_SelectedAnswer(),
  local!Temp: stripwith(
    local!selectedAnswer.SelectedAnswer,
    "ZYWX[]:"
  ),
  /*local!result: intersection(local!correctAnswer, local!Temp),*/
  /*local!score: length(local!result),*/

  local!submit: false,
  {
    a!sectionLayout(
      label: "xxx",
      contents: {
        a!forEach(
          items: local!question,
          expression: a!localVariables(
            local!currentQuestion: fv!index,
            {
              a!columnsLayout(
                columns: {
                  a!columnLayout(
                    contents: a!checkboxField(
                      choiceLabels: {
                        a!forEach(
                          items: enumerate(local!numberOfAnswers),
                          expression: index(
                            split(stripwith(local!option, "[]ZYWX:"), ","),
                            if(
                              local!currentQuestion = 0,
                              fv!index,
                              fv!index + local!numberOfAnswers * (local!currentQuestion - 1)
                            )
                          )
                        )
                      },
                      choiceValues: {
                        a!forEach(
                          items: enumerate(local!numberOfAnswers),
                          expression: index(
                            split(local!option, ","),
                            if(
                              local!currentQuestion = 0,
                              fv!item,
                              fv!index + local!numberOfAnswers * (local!currentQuestion - 1)
                            )
                          )
                        )
                      },
                      label: fv!index & ".  " & fv!item,
                      labelPosition: "ABOVE",
                      value: local!selectedAnswer.SelectedAnswer[local!currentQuestion],
                      saveInto:
                      a!save(
                        local!selectedAnswer.SelectedAnswer[local!currentQuestion],
                        save!value
                      ),
                      validations: {}
                    )
                  )
                  
                },
                alignVertical: "TOP"
              ),
              a!sectionLayout(
                label: "",
                contents: {
                  a!richTextDisplayField(
                    label: "Correct Answer : ",
                    labelPosition: "ABOVE",
                    value: a!richTextItem(
                      text: {
                        a!forEach(
                          items: local!currentQuestion,
                          expression: index(
                            local!correctAnswer,
                            if(
                              local!currentQuestion = 0,
                              "",
                              fv!index + 1 * (local!currentQuestion - 1)
                            )
                          )
                        )

                      },
                      color: "POSITIVE",
                      size: "MEDIUM",
                      style: "EMPHASIS"
                    ),
                    showWhen: local!submit

                  )

                }
              )

            }

          )
        )
      },
      marginBelow: "STANDARD"

    ),
    /*a!timeDisplayField(*/
    /*label:"Time Lapsed",*/
    /*value:time(now())*/
    /*),*/
    a!buttonArrayLayout(
      buttons: {
        a!buttonWidget(
          label: "Check Score",
          icon: "thumbs-up",
          iconPosition: "END",
          saveInto: {

            /*a!save(local!submit, save!value),*/
            /*a!save(ri!score.score,local!score)*/
          },
          /*submit: true,*/

          style: "GHOST"
        ),
        a!buttonWidget(
          label:"close",
          value:"close",
          saveInto: ri!buttonAction,
          submit:true,
          style: "SOLID"


        )

      },
      align: "CENTER"

    ),
    a!sectionLayout(
      labelColor: "POSITIVE",
      contents: {
        a!columnsLayout(
          columns: {
            a!columnLayout(
              contents: {
                a!richTextDisplayField(
                  labelPosition: "ADJACENT",

                  value:{a!richTextItem(
                    text: "Your Score is  ",
                    color: "ACCENT",
                    size: "LARGE",
                    style: "STRONG"

                  ),
                  a!richTextItem(
                    /*text: { local!score },*/
                    color: "ACCENT",
                    size: "LARGE",
                    style: "STRONG"


                  )},
                  showWhen: local!submit,
                  marginAbove: "STANDARD"

                )
              }
            )

          }
        )
      },
      isInitiallyCollapsed: true,
      dividerWeight: "MEDIUM",
      dividerColor: "ACCENT",
      marginAbove: "STANDARD"
    )


  }
)

I had used index() here & now am able to select multiple answers for a single question but if i select the answer for another question than the first selected answer gets vanished. Is there any way to resolve this and store all the selected values in local?

updated code-

value: index(local!selectedAnswer.SelectedAnswer,local!currentQuestion),
saveInto: a!save(
                index(local!selectedAnswer.SelectedAnswer,local!currentQuestion),
                save!value
                ),

I had used index() here & now am able to select multiple answers for a single question but if i select the answer for another question than the first selected answer gets vanished. Is there any way to resolve this and store all the selected values in local?

updated code-

value: index(local!selectedAnswer.SelectedAnswer,local!currentQuestion),
saveInto: a!save(
                index(local!selectedAnswer.SelectedAnswer,local!currentQuestion),
                save!value
                ),

Firstly, the index function should have a third parameter which is the default value to return if the index isn't present. Secondly, when using list/array/dictionary/map in save into, avoid using index. You should only use it in the value parameter. 

And now, try verifying that the variable you are trying to save in accepts multiple values, and try wrapping your save!value in a!flatten() function. 

thanks for your response. could you suggest me how to fix this error. 

Here I had selected 2 values and got this error.

Sorry, but this image doesn't load for me. Can you try uploading it again?

/resized-image/__size/640x480/__key/communityserver-discussions-components-files/13/8816.error1.png

It is clear. You have misconfigured a rule by passing in 2 parameters when it only accepts one. It is present on line 27. 

Did you check the Rule - "I" at line 27 ?