A friend has had problems uploading Typst-generated PDFs to the Internet Archive (an unhelpful “Syntax error detected in pdf data”) so I offered to take a look. Checking with pdfinfo, from poppler-utils, which just reads the header, I see e.g. (note line 7):
Title: Minimal
Creator: Typst 0.14.2
CreationDate: Mon Feb 23 21:09:57 2026 GMT
ModDate: Mon Feb 23 21:09:57 2026 GMT
Custom Metadata: no
Metadata Stream: yes
Syntax Error: Suspects object is wrong type (boolean)
Tagged: yes
UserProperties: no
Suspects: no
Form: none
JavaScript: no
Pages: 1
Encrypted: no
Page size: 595.276 x 841.89 pts (A4)
Page rot: 0
File size: 10281 bytes
Optimized: no
PDF version: 1.7
This happens even with a minimal Typst source. It does not happen with --pdf-standard 1.4, 1.5, 2,0, or the a-1 or a-4 formats; i.e. it’s only those formats that produce a PDF Version field value of 1.6 or 1.7. (I think “suspects” was introduced in 1.6.)
I don’t know PDF internals well enough to track it down further, but this does at least appear to be a violation of what PDF parsers expect.