The export carried its provenance comment above the header, and every spreadsheet
importer treats line one as the header — so the scope sentence became the column names
and the real header became the first data row. A single-column line above a sixty-eight
column table is what "glitched" looks like on screen.
Three other explanations were plausible and all three are wrong, measured before
anything changed: the file is comma-separated, not tab-separated, so the tabs in the
report were terminal rendering rather than bytes; the escaper is genuinely RFC-4180, and
embedded commas, quotes and newlines all survive a strict parser round trip; and
injection-prefixed cells were already neutralised. Only the position was wrong, and
chasing the other three would have produced churn and no fix.
The provenance line moves to the end rather than away. It records which filters produced
the file, which is the difference between a dataset and an anecdote, and a trailing
single-column row lands as one populated cell instead of destroying the column mapping.
The field counter that read line two moved with it — left alone it would have counted
the first data row, usually the same number, so it would have looked right and been
wrong.
A new check parses the export the way a spreadsheet would, which no existing gate did:
forty-six checks and not one read the file. It extracts the shipped escaper rather than
restating the rule, so it cannot agree with itself while the product disagrees.
Negative-tested by putting the comment back on top.
