To reproduce:
1. Add a RadGridView and a RadButton.
2. Populate the grid with data and call the BestFitColumns( BestFitColumnMode.AllCells) method (or resize the columns).
3. Set its RightToLeft property to Windows.Forms.RightToLeft.Yes.
3. In the RadButton.Click event handler call the RadGridView.PrintPreview(). As a result the columns are shrunk. Please see the attached gif file.

Workaround:

Private Sub RadButton1_Click(sender As Object, e As EventArgs) Handles RadButton1.Click
    Me.RadGridView1.BeginUpdate()
    Me.RadGridView1.PrintPreview()
    Me.RadGridView1.EndUpdate()
    Me.RadGridView1.BestFitColumns(BestFitColumnMode.AllCells)
End Sub