A contact shows a "Missing merge data" alert icon. This means a field required by your template is empty for this contact and would therefore render as an empty string in the PDF.
Steps (resolve)
Spot the contacts marked with the alert icon in the campaign table.
Use the dedicated filter to show only these contacts.
Fill in the missing fields (name, address, custom field...) then run again.
Good to know
Only contact-dependent fields are counted. Sender-side fields (user.*, company.*, campaign.*) and computed values (qr.*, today, short URL...) are always resolvable and never flagged as missing.
"Missing" means exactly "renders as an empty string": the logic on the table side and on the merge kit export side is identical (lib/mergeRequirements.ts).
On the table side, only the fields the client knows are judged; an unmapped custom field can have a value server-side, so the export applies the full check.
Exclusion at export: contacts with missing data can be set aside from the merge kit to avoid PDFs with holes.
---
