Unable to Update DataTable, No Primary Key

I am updating a DataTable, and when I do it says Table doesn't have a primary key. I changed how I created the table, and added a PrimaryKey, so what's going on?

I create the table, add columns, and add rows with data, and some blank values. The DEBUG code right after it's populated works fine.

I then want to populate some of those blank values, but when I do I get the error.

Here is my code:

DataRow workrow;
DataTable ReasonCodeTable = new();

DataColumn dc1 = new();
dc1.ColumnName = "Reason Code";
dc1.DataType = typeof(string);

DataColumn dc2 = new();
dc2.ColumnName = "LocationID";
dc2.DataType = typeof(string);

DataColumn dc3 = new();
dc3.ColumnName = "Location";
dc3.DataType = typeof(string);

DataColumn dc4 = new();
dc4.ColumnName = "Issue";
dc4.DataType = typeof(string);

DataColumn dc5 = new();
dc5.ColumnName = "Description";
dc5.DataType = typeof(string);

DataColumn dc6 = new();
dc6.ColumnName = "Who Edited";
dc6.DataType = typeof(string);

DataColumn dc7 = new();
dc7.ColumnName = "Last Edit (UTC)";
dc7.DataType = typeof(string);


ReasonCodeTable.Columns.Add(dc1);
ReasonCodeTable.Columns.Add(dc2);
ReasonCodeTable.Columns.Add(dc3);
ReasonCodeTable.Columns.Add(dc4);
ReasonCodeTable.Columns.Add(dc5);
ReasonCodeTable.Columns.Add(dc6);
ReasonCodeTable.Columns.Add(dc7);
ReasonCodeTable.PrimaryKey = new DataColumn[] { dc1, dc2 };

// Builds ReasonCodeTable
foreach (string code in codeList)
{
    foreach (KeyValuePair<String, String> loc in Locations)
    {
        workrow = ReasonCodeTable.NewRow();
        workrow["Reason Code"] = code;
        workrow["LocationID"] = loc.Key;
        workrow["Location"] = loc.Value;
        workrow["Issue"] = "";
        workrow["Description"] = "";
        workrow["Who Edited"] = "";
        workrow["Last Edit (UTC)"] = "";
        ReasonCodeTable.Rows.Add(workrow);
    }
}


/*** DEBUG BEGIN ***/
foreach(DataRow dr in ReasonCodeTable.Rows)
{
    for (int cnt = 0; cnt < ReasonCodeTable.Columns.Count; cnt++)
        Console.WriteLine($"{ReasonCodeTable.Columns[cnt].ColumnName}: {dr[cnt]}");
    Console.WriteLine($"");
}
/*** DEBUG END ***/


foreach (DataRow _rcdr in ReasonCodeTable.Rows)
{
    foreach (DataRow _dr in p21CodeTable.Rows)
    {
        if ( (p21CodeTable.Rows.Find(_rcdr["Reason Code"]) != null) && (p21CodeTable.Rows.Find("P21") != null) )
        {
            _rcdr["Desciption"] = _dr["description"];
            _rcdr["Who Edited"] = _dr["editwho"];
            _rcdr["Last Edit (UTC)"] = _dr["editdate"];
        }
    }
}

/*** DEBUG BEGIN ***/
foreach(DataRow dr in ReasonCodeTable.Rows)
{
    for (int cnt = 0; cnt < ReasonCodeTable.Columns.Count; cnt++)
        Console.WriteLine($"{ReasonCodeTable.Columns[cnt].ColumnName}: {dr[cnt]}");
    Console.WriteLine($"");
}
/*** DEBUG END ***/

R64CodeTable:

company: IBM
code: 10
description: Inventory Count
editdate: 2020-05-19
editwho: User12

company: IBM
code: 11
description: Data Error
editdate: 2021-06-28
editwho: User12

company: IBM
code: 12
description: Warehouse Error
editdate: 2021-08-19
editwho: User06

ReasonCodeTable after initial population:

Reason Code: 10
LocationID: R64
Location: R64
Issue:
Description:
Who Edited:
Last Edit (UTC):

Reason Code: 10
LocationID: WH1
Location: Chicago
Issue:
Description:
Who Edited:
Last Edit (UTC):

Reason Code: 11
LocationID: R64
Location: R64
Issue:
Description:
Who Edited:
Last Edit (UTC):

ReasonCodeTable how it should look after update:

Reason Code: 10
LocationID: R64
Location: R64
Issue:
Description: Inventory Count
Who Edited: User12
Last Edit (UTC): 2020-05-19

Reason Code: 10
LocationID: WH1
Location: Chicago
Issue:
Description:
Who Edited:
Last Edit (UTC):

Reason Code: 11
LocationID: R64
Location: R64
Issue:
Description: Data Error
Who Edited: User12
Last Edit (UTC): 2021-06-28

I don't understand what's going on with the primary key.