Issue with a!startProcessLink function when using in a!gridField (Version 19.3)

The code you've posted looks correct assuming I'm not missing something.  Just for comparison could you post the approximately same snippet from the old version that still used the old grid component?  BTW, I recommend when posting code like this, you use "Insert --> Insert Code" from the menu to create a code box and paste the code there, as this retains indentation and generally makes it easier to read.

Thanks for the reply. Please find the old code below which was working fine.

 a!gridField_19r1(
              label: "",
              totalCount: local!policyPropertyGrid.totalCount,
              columns: { 
              a!gridTextColumn(
                  label: "Edit",
                  data: a!forEach(
                    items: index(
                      local!policyPropertyGrid.data,
                      "policyId",
                      ""
                    ),
                    expression: "Edit Property"
                  ),
                  links: a!forEach(
                    items: index(
                      local!policyPropertyGrid.data,
                      "policyId",
                      ""
                    ),
                    expression: a!startProcessLink(
                      label: "Edit",
                      processModel: cons!POL_PROPERTY_PM,
                      processParameters: {
                        policyId: fv!item,
                        
                      }
                    )
                )
            )
        }
        
        value: local!pagingInfo,
        saveInto: local!pagingInfo
    )

Unless there's a typo or something that i'm missing (always a chance), the new version seems correct.  If you can verify this behavior stays the same in a different interface / process model, i suppose it could be a product bug which you could report to Appian.

Edit to add: I made my own small test app (note this is in Appian 19.4 not 19.3), and it seems to work correctly when I try it.  Here's my interface, and it just points to a simple PM with a single parameter.

a!localVariables(
  local!items: {
    {
      id: 1,
      name: "apple"
    },
    {
      id: 2,
      name: "orange"
    },
    {
      id: 3,
      name: "strawberry"
    }
  },
  a!sectionLayout(
    label: "Testing",
    contents: {
      a!gridField(
        data: local!items,
        columns: {
          a!gridColumn(
            label: "Item",
            value: fv!row.name
          ),
          a!gridColumn(
            label: "Link",
            value: a!richTextDisplayField(
              value: {
                a!richTextItem(
                  text: "(id: " & fv!row.id & ")",
                  link: a!startProcessLink(
                    processModel: cons!TEST_GRID_TARGET_PM,
                    processParameters: {
                      testParameter: fv!row.id
                    }
                  )
                )
              }
            )
          )
        }
      )
    }
  )
)

Unless there's a typo or something that i'm missing (always a chance), the new version seems correct.  If you can verify this behavior stays the same in a different interface / process model, i suppose it could be a product bug which you could report to Appian.

Edit to add: I made my own small test app (note this is in Appian 19.4 not 19.3), and it seems to work correctly when I try it.  Here's my interface, and it just points to a simple PM with a single parameter.

a!localVariables(
  local!items: {
    {
      id: 1,
      name: "apple"
    },
    {
      id: 2,
      name: "orange"
    },
    {
      id: 3,
      name: "strawberry"
    }
  },
  a!sectionLayout(
    label: "Testing",
    contents: {
      a!gridField(
        data: local!items,
        columns: {
          a!gridColumn(
            label: "Item",
            value: fv!row.name
          ),
          a!gridColumn(
            label: "Link",
            value: a!richTextDisplayField(
              value: {
                a!richTextItem(
                  text: "(id: " & fv!row.id & ")",
                  link: a!startProcessLink(
                    processModel: cons!TEST_GRID_TARGET_PM,
                    processParameters: {
                      testParameter: fv!row.id
                    }
                  )
                )
              }
            )
          )
        }
      )
    }
  )
)

Thanks Mike for the help. I tried the sample code shared by you and it is working fine. On further analysis, I have identified the issue and fixed it. Dataset (Output of a stored procedure) was causing the problem. Identifier value present in the dataset was not correct and created this issue. 

Thanks,
Abin

Cool, thanks for confirming.  BTW, if you feel like my answer helped you, I'd appreciate it if you can mark my answer as "verified" and/or upvote it :)