Problem with changing position in a editable grid backed with records

Im trying to move a row of data through the table, I got the down movement right but the up movement doesn't seem to work, it moves two row up instead of just one and doesn't update the previous position value to the new one, here's the code (relevant from line 39 downwards):

a!localVariables(
  local!properties:rule!MM_getPropertiesByType(type: ri!propertyType),
  {
  a!gridLayout(
    label: ri!propertiesLiteral,
    labelPosition: "ABOVE",
    headerCells: {
      a!gridLayoutHeaderCell(label: ""),
      a!gridLayoutHeaderCell(label: "Value"),
      a!gridLayoutHeaderCell(label: ""),
      a!gridLayoutHeaderCell(label: "")
    },
    columnConfigs: {
      a!gridLayoutColumnConfig(
        width: "ICON"
      ),
      a!gridLayoutColumnConfig(
        weight: 10
      ),
      a!gridLayoutColumnConfig(
        width: "ICON"
      ),
      a!gridLayoutColumnConfig(
        width: "ICON"
      )
    },
    rows: {
      a!forEach(
        items: local!properties,
        expression: a!gridRowLayout(
          contents: {
            a!richTextDisplayField(
              labelPosition: "COLLAPSED",
              value: {
                if(
                  fv!index=1,
                  {},
                  a!richTextIcon(
                    icon: "arrow-up",
                    link: a!dynamicLink(
                      saveInto: {
                        a!save(
                          local!properties,
                          insert(
                            local!properties,
                            fv!item,
                            fv!index-1
                          )
                        ),
                        a!save(
                          local!properties,
                          remove(
                            local!properties
                            fv!index+1
                          )
                        )
                      }
                    )
                  )
                ),
                if(
                  fv!isLast,
                  {},
                  a!richTextIcon(
                    icon: "arrow-down",
                    link: a!dynamicLink(
                      saveInto: {
                        a!save(
                          local!properties,
                          insert(
                            local!properties,
                            fv!item,
                            fv!index+2
                          )
                        ),
                        a!save(
                          local!properties,
                          remove(
                            local!properties,
                            fv!index
                          )
                        )
                      }
                    )
                  )
                )
              }
            ),
            a!textField(
              value: fv!item['recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{041a7f43-dfd1-4b07-aaed-48e305712f4e}value'],
              saveInto:{
                fv!item['recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{041a7f43-dfd1-4b07-aaed-48e305712f4e}value'],
                a!save(
                  fv!item['recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{2612aa2c-ca09-4a4f-87a1-f66b6f08303c}modifiedOn'],
                  now()
                )
              }
            ),
            a!richTextDisplayField(
              labelPosition: "COLLAPSED",
              value: {
                a!richTextIcon(
                  icon: "dot-circle-large",
                  color: if(
                    fv!item['recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{18bf5c84-4f3f-4566-a572-6d8ba5dd5285}active'],
                    "POSITIVE",
                    "NEGATIVE"
                  ),
                  link: a!dynamicLink(
                    saveInto: {
                      a!save(
                        fv!item['recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{18bf5c84-4f3f-4566-a572-6d8ba5dd5285}active'],
                        if(fv!item['recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{18bf5c84-4f3f-4566-a572-6d8ba5dd5285}active'],false,true)
                      )
                    }
                  )
                )
              }
            ),
            a!richTextDisplayField(
              labelPosition: "COLLAPSED",
              value: {
                a!richTextIcon(
                  icon: "times",
                  color: "NEGATIVE",
                  link: a!dynamicLink(
                    saveInto: {
                      a!save(
                        local!properties,
                        remove(local!properties,fv!index)
                      )
                    }
                  )
                )
              }
            )
          }
        )
      )
    },
    shadeAlternateRows: true,
    addRowLink:a!dynamicLink(
      label: "Add",
      saveInto: {
        a!save(
          local!properties,
          append(local!properties,'recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property'(
            'recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{54637987-ef12-4057-b4c3-c898561cb626}type': ri!propertyType,
            'recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{832f6a1b-9643-4fd5-a389-0556c2ee74a6}order': count(local!properties)+1,
            'recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{18bf5c84-4f3f-4566-a572-6d8ba5dd5285}active': true,
            'recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{39dea2b9-c9f9-4b57-9aeb-62cf86ab5656}createdBy': loggedInUser(),
            'recordType!{5ebb976a-556f-4033-b1d7-9e5976ab963d}MM Property.fields.{2612aa2c-ca09-4a4f-87a1-f66b6f08303c}modifiedOn': now()
          ))
        )
      }
    )
  )
}
)