Validation Group is not working properly

Personally I've always found ValidationGroup functionality to be unintuitive and cumbersome to implement, use, and/or test, with results that are inconsistent with expectations or designed intentions.  Thus I typically use other methods to enforce validations under certain circumstances, beginning with making sure my forms are scope-limited where possible, and also, abstracting certain form functionality using local variables (such as variables keeping track of validation status of certain elements if needed).  Without knowing a bit more detail about your particular requirement or intended design, it's hard to offer much more of a concrete suggestion than this.

Thanks Mike. The use case was to validate a date against the other date only on form submission. The validation group does not give the desired result for my use case. I have used a local variable to set a flag based on the validation on submit, and added validations based on this local variable in the date fields. Now it works. 

Cool, thanks for confirming - it sounds like you've figured out approximately what I was referring to then :)

Yes Mike. But I am facing one issue again. The validation works fine in the interface when I run it as stand alone, but not when I start the related action where This interface is added as a start form. 

a!localVariables(
  local!testData: {
    {
      serialNumber: 1,
      date1: today(),
      date2: today() + 10
    },
    {
      serialNumber: 2,
      date1: today() + 10,
      date2: today() + 20
    },
    
  },
  local!isValidMcdDate: a!refreshVariable(
    value: a!forEach(local!testData, null),
    refreshAlways: false()
  ),
  a!formLayout(
    contents: {
      a!boxLayout(
        label: "Test Data",
        contents: a!gridLayout(
          emptyGridMessage: "No items available",
          headerCells: {
            a!gridLayoutHeaderCell(label: "Serial Number"),
            a!forEach(
              items: local!testData,
              expression: a!gridLayoutHeaderCell(label: fv!item.serialNumber)
            )
          },
          rows: {
            a!gridRowLayout(
              contents: {
                a!richTextDisplayField(
                  value: a!richTextItem_18r1(text: "Serial Number", )
                ),
                a!forEach(
                  local!testData,
                  a!tagField(
                    tags: a!tagItem(
                      text: fv!item.serialNumber,
                      textColor: "STANDARD"
                    )
                  )
                )
              }
            ),
            a!gridRowLayout(
              contents: {
                a!richTextDisplayField(value: a!richTextItem(text: "Date 1")),
                a!forEach(
                  local!testData,
                  a!dateField(
                    label: "Date 1",
                    labelPosition: "ADJACENT",
                    value: fv!item.date1,
                    saveInto: fv!item.date1,
                    validations: if(local!isValidMcdDate[fv!index], "Error", "")
                  )
                )
              }
            ),
            a!gridRowLayout(
              contents: {
                a!richTextDisplayField(value: a!richTextItem(text: "Date 2")),
                a!forEach(
                  local!testData,
                  a!dateField(
                    label: "Date 2",
                    labelPosition: "ADJACENT",
                    value: fv!item.date2,
                    saveInto: fv!item.date2,
                    
                  )
                )
              }
            ),
            
          }
        )
      )
    },
    buttons: a!buttonLayout(
      primaryButtons: {
        a!buttonWidget(
          label: "Submit",
          value: false,
          saveInto: {
            a!save(
              local!isValidMcdDate,
              a!forEach(
                local!testData,
                if(
                  todate(fv!item.date1) > todate(fv!item.date2),
                  true(),
                  null
                )
              )
            ),
            
          },
          submit: true,
          style: "PRIMARY",
          validate: true(),
          
        )
      },
      secondaryButtons: {
        a!buttonWidget(
          label: "Cancel",
          value: true,
          saveInto: ri!cancel,
          submit: true,
          style: "NORMAL",
          validate: false
        )
      }
    ),
    
  )
)

Appreciate your help.

Thanks for posting some generic code I could just copy into an interface editor, that's really helpful and I have it working on my environment now.  Could you talk a bit more about what exactly the validation is meant to do, and what you would like the end user's experience to be, step by step?  I see you're setting the validation local variable upon click of the Submit button, though i'm a little unclear why you're setting the value there instead of upon initial declaration and allowing the validation error to show up naturally as soon as the invalid data is entered.

Thanks for posting some generic code I could just copy into an interface editor, that's really helpful and I have it working on my environment now.  Could you talk a bit more about what exactly the validation is meant to do, and what you would like the end user's experience to be, step by step?  I see you're setting the validation local variable upon click of the Submit button, though i'm a little unclear why you're setting the value there instead of upon initial declaration and allowing the validation error to show up naturally as soon as the invalid data is entered.