Issues with row selection in a grid

Hi All,

I'm facing some issues with the grid selection in a grid. I'm not sure if it is a bug. I tried using the design pattern 'Master details' https://docs.appian.com/suite/help/20.1/master-detail-pattern.html . But I noticed, the selected row is getting deselected immediately. I'm still trying to understand how the row is getting highlighed in the design pattern even though its value is not saved into 'SelectionSaveInto' parameter. Below is my code which is similar to design pattern. I initially tried with a query rule for the data, but facing the same issue even while providing raw data. My current env is 20.1

{
a!localVariables(

local!employees: {

{comments: "Consideration should be given to annual re-inspection and removal during future refurbishment works.", dateRemoved: "", controlMeasure: "", riskRating: "P4", condition: "S", photoNo: "1,2", sampleNo: "Previously Identified", matrix: "B", type: "CH,AM", location: "Underside of the awning between the Transmitter Building (Equipment Building) and EPP Building", descriptionMaterial: "Fibre cement sheeting", dateIdentified: "13/04/2015", siteName: "Mt Lofty", siteNo: 5018, id: 6}, 
{comments: "Remove as soon as practicable. All ground maintenance works within the vicinity of the cable pit should be suspended immediately until removal works have been completed. If material is removed by a licenced asbestos removal contractor, a clearance inspection and subsequent clearance certificate may be required", dateRemoved: "", controlMeasure: "", riskRating: "P2", condition: "P", photoNo: "3,4", sampleNo: "GB05", matrix: "B", type: "CH,AM", location: "Cable pit surround to the north of the Transmitter Building (Equipment Building) and south of the satellite dishes", descriptionMaterial: "Fibre cement", dateIdentified: "13/04/2015", siteName: "Mt Lofty", siteNo: 5018, id: 7}, 
{comments: "Remove as soon as practicable. All ground maintenance works should ve suspended immediately until removal works have been completed. If material is removed by a licenced asbestos contractor, a clearance inspection and subsequent clearance certificate may be required", dateRemoved: "", controlMeasure: "", riskRating: "P3", condition: "F", photoNo: "7,8", sampleNo: "Similar material as GB06", matrix: "B", type: "NT(CH,AM,CR)", location: "Cable pit surround to the western elevation of the EPP building", descriptionMaterial: "Presumed asbestos containing fibre cement", dateIdentified: "13/04/2015", siteName: "Mt Lofty", siteNo: 5018, id: 8}, 
{comments: "Label as asbestos containing material. Encapsulate exposed edges and surfaces. Consideration should be given to annual re-inspection and removal during future refurbishment works", dateRemoved: "", controlMeasure: "", riskRating: "P3", condition: "F", photoNo: "12,13", sampleNo: "NT", matrix: "B", type: "NT", location: "Pipe beneath the Community FM antenna (the pipe extended beneath ground surface in an unknown direction).", descriptionMaterial: "Presumed asbestos containing fibre cement", dateIdentified: "13/04/2015", siteName: "Mt Lofty", siteNo: 5018, id: 9}
},

/* This variable is used to pass the full row of data on the selected item to the part of the interface showing the details of the selected item. */
/* Here we are pre-selecting a row by indexing into the sample data; however, the data for the pre-selected row would typically be passed in as a *
* rule input or generated with a query. */
local!selectedEmployee,

{
a!columnsLayout(
columns: {
a!columnLayout(
contents: {
a!sectionLayout(
label: "Employees",
contents: {
a!gridField(
/* Replace the dummy data with a query, rule, or function that returns a datasubset and uses fv!pagingInfo as the paging configuration. */
data: todatasubset(local!employees,fv!pagingInfo),
columns: {
a!gridColumn(
label: "Date identified",
value: fv!row.dateIdentified
),
a!gridColumn(
label: "Material",
value: fv!row.descriptionMaterial
)
},
pageSize: 3,
selectable: true,
selectionStyle: "CHECKBOX",
selectionValue: index(local!selectedEmployee, "id", {}),
selectionSaveInto: {
/* This save replaces the value of the previously selected item with that of the newly selected item, ensuring only one item can be selected at once.*/
a!save(
local!selectedEmployee,
if(
length(fv!selectedRows) > 0,
fv!selectedRows[length(fv!selectedRows)],
null
)
),
/*a!save(local!selectedId,null)*/
},
shadeAlternateRows: false,
rowHeader: 1
)
}
)
}
) 

},
stackWhen: {
"PHONE",
"TABLET_PORTRAIT"
}
),
/*a!paragraphField(*/
/*value: index(local!selectedEmployee, "id", {})*/
/*)*/
}
)
}