I just gave this a quick try. I entered "1,2" in the first cell and "3" in the second cell, no quotes. Then I saved, and the raw output looks like this:

    1,2,3,,,,,,,,
    ,,,,,,,,,
    ,,,,,,,,,
    ... (100 lines total)

Most importantly, the comma in "1,2" was not escaped or quoted, so opening the same CSV that I saved produces a different result.

But also, all the extra commas is pretty weird, at least by default. And I don't see any configuration for that anyway.