Created Unassigned: Formula is broken when you copy [9412]

<Formula of the source cell>
=R[5]C-1

var wb = new XLWorkbook(@"C:\Sample.xlsx");
var wsSource = wb.Worksheet(1);
wsSource.CopyTo("Copy");
wb.SaveAs(@"C:\Sample.xlsx");

<Formula of the destination cell>
=R[5]C[-1]