It can get even worse. In Excel 2000 days (and may still occur today), it was possible to load in a CSV file, make NO edits, save it as CSV and then when you tried to reload it into Excel it would fail with invalid format errors.
That's right, the specification that Excel used when SAVING CSV files is actually different to the specification used when LOADING CSV files.
I can't even start to explain my reaction when I found this out the first time.