Cloudflare: Cloudflare does not sufficiently truncate credit card numbers in invoices

When a Cloudflare user has a paid account, but Cloudflare can't process the user's credit card, Cloudflare emails the user from [email protected], subject line "Cloudflare Failed Taking Payment for INV-D1234567". The email contains an attachment, "2017-11-19CloudflareINV-D1234567.pdf", a PDF...