Sheet data without column header lost

[bosschaert]

If I add some data to a sheet, but don't add a column header, this data is not saved.

Expected Behaviour

I would expect everything that's entered on a sheet to be saved, regardless of where it's entered.

Actual Behaviour

Only data in a column that has a column header is saved, data in a column without a header is lost.

Steps to Reproduce

For example create a sheet with this content:

Then press reload on the browser and see that the data has disappeared: