PDF/A-1b generation does not pass format validation

[julien-gonzalez]

Hello,
I'm trying to generate PDF/A-1b documents that must be later uploaded to a service checking the format is respected.
I'm using WeasyPrint version 60.2.

The command I used is :
weasyprint --pdf-variant pdf/a-1b --pdf-identifier 59a2255c-14a7-47e9-816d-66c9ffcab69a simple-page.html result.pdf

The 2 files, html and pdf results are enclosed to this issue : html-and-result.zip

I'm passing the result.pdf file against PDF/A-1b validators (https://demo.verapdf.org/ is one of them).
The validators tell me that the document isn't a valid PDF/A-1b document because it's not respecting the Rule 6.7.2-2 :

Metadata object stream dictionaries shall not contain the Filter key.

Following the message shown by weasyprint during PDF/A-1b generation, I'm opening an issue to check if there a solution to my problem.

Thanks in advance for you help.