PDFA/1B - Wrong Conversion

Hi Everyone,
I am testing the conversion from PDF to PDFA/1B using the sample provided on the site.
Even if the conversion and the validation succeded, If I validate the PDFA/1B output using Acrobat or other tools I got this error:

TrueType font has differences to standard encodings but is not a symbolic font (440 matches on 8 pages) - 1, 2, 3, 4, 5, 6, 7, 8

Can someone help me ?

I am testing the conversion from PDF to PDFA/1B using the sample provided on the site.

Which exact sample?
The ones here are using 2B, not 1B.

I modified one to convert newsletter.pdf to 1B, and ran against Adobe, and it passed.

Could you please be more specific in what you tried (provide code, and output file).

TrueType font has differences to standard encodings but is not a symbolic font (440 matches on 8 pages) - 1, 2, 3, 4, 5, 6, 7, 8

Technically the PDF/A standard does not cover fonts (of which PDF supports different font formats), just as PDF/A doesn’t cover image formats. Either way, PDF works closely with the PDF Association and the open source VeraPDF PDF/A validator.

Please see these links for more info.