Opening and resaving this spreadsheet causes it to become corrupt

Created originally on Bitbucket by dbereznyi (Daniel Bereznyi)

Just doing

#!python

import openpyxl as xl
wb = xl.load_workbook("sheet.xlsx")
wb.save("sheet_out.xlsx")

causes sheet_out.xlsx to be saved incorrectly with Excel 2016 reporting the file as being corrupt. The file is opened correctly by LibreOffice 6.0.0.3 (x64). Validating sheet_out.xlsx in Open XML SDK 2.5 Productivity Tool generates this:

Attachments: sheet.xlsx