This can happen if the objects aren't fully released from memory. After deleting the sheet, explicitly set the sheet object to Nothing to release it from memory:
Dim ws As Worksheet
Set ws = ActiveWorkbook.Sheets("Output_Final")
ws.Delete
Set ws = Nothing
See also Remove a non-existant Sheet in VBA, VBA code deletes it's own sheet, leaving a "ghost" sheet behind, GHOST Worksheet in Project Explorer - How to Delete It?