For each PDF/A-1 validation issue we try to explain what it means and, if possible how to resolve it. For a more technical explanation of the issue we quote the related section of the ISO 19005-1 PDF/A Specification.
Many PDF compression products strip out "extra" whitespace like an end-of-line if it precedes an unambiguous PDF delimiter like <<. While these files may work fine in Acrobat Reader, they are not PDF or PDF/A compliant.
How can I fix it?
Open your PDF file in Solid PDF Tools and then File | Save As PDF/A. This will correct the formatting of your PDF/A file.
6.1.8 - ISO 19005-1 PDF/A Specification:
The object number and generation number shall be separated by a single white-space character. The generation number and obj keyword shall be separated by a single white-space character. The object number and endobj keyword shall each be preceded by an EOL marker. The obj and endobj keywords shall each be followed by an EOL marker.