Qualified signature showing invalid only in Adobe Reader

Question

Here is PDF with qualified electronic signature pdf-qualified.invalid.pdf

All validation apps show it correct as PAdES-BASELINE-LT, however Adobe Reader shows it invalid. What is wrong with this digitally signed PDF? It includes CAdES-BASELINE-LT signature, all OCSPs, all needed Certs.

Adobe reader shows its invalid

EU validation shows signature is valid at https://ec.europa.eu/cefdigital/DSS/webapp-demo/validation

DigiDoc4 app shows signature is valid

https://www.eparaksts.lv/ shows it is valid

Here we can see the PDF structure related to the digital signature

Answer 1

CAdES signature was baseline-LT level. When downgrading CAdES to baseline-T then it started working.

I would say its Adobe Reader bug unless some specification explicitly says that CAdES in baseline-LT level is not allowed.