Programatically setting CheckBox value in DataGridView on another Tab does not commit

I have a form with two tabs, each with a DataGridView. DGV1 on Tab1 is bound to a DataTable on form load. DGV2 on Tab2 is not bound on form load, but includes a CheckBoxColumn to be utilized later.

When I select a row in DGV1, DGV2 is populated and I set each checkbox on DGV2 to True.

However, after a cell in DGV1 is clicked and DGV2 is subsequently populated and the checkboxes are set to True, they are reverted to Nothing when I first go to Tab2. However, once I have "seen" DGV2 by clicking the second tab, I can go back to DGV1 and click the same row, and now the checkboxes will actually be checked.

I have tried using Refresh and RefreshEdit to no avail.

Public Class Form1       
    Private ConnectionString As String = "..."

    Private Function GetDataTable(selectString) As DataTable
        Dim adapter As New SqlDataAdapter(selectString, ConnectionString)
        Dim dt As New DataTable
        Dim bs As New BindingSource

        adapter.Fill(dt)
        bs.DataSource = dt

        Return dt
    End Function

    Private Sub Form1_Load(...) Handles Me.Load
        DGV1.DataSource = GetDataTable("SELECT * FROM ...")
    End Sub

    Private Sub DGV1_CellClick(...) Handles DGV1.CellClick
        DGV2.DataSource = GetDataTable("SELECT * FROM ...")

        For i = 0 To dt.Rows.Count - 1
            DGV2.Item(0, i).value = True
        Next
    End Sub
End Class

This seems to only apply to the CheckBoxColumn, as I can programatically edit other non-checkbox cells in the same manner and the changes are committed correctly. Any suggestions?