Fonts are not embedded in the Draft version of source PDF files prior to loading into Vault. The first page in the new Draft version of a PDF source file displays similar content to the previous version.
Some of the fonts are not embedded in the new Draft version of the source PDF file before it is uploaded into Vault.
If this behavior is seen on a document, please embed all fonts in the PDF source file using Adobe Acrobat Pro.
Once this is done, the PDF source file successfully loads into Vault.
PDF Fonts: Font Embedding and Substitution