Thanks for your patience.
Our product team has investigated earlier reported issue and according to their findings, there were some fonts in the documents which contain no character map (CMap), which was why full extraction of text was impossible. Please note that, this is about fonts with keys ‘F2’ and ‘F4’, which are Type0 fonts with Identity-H encoding and CIDFontType2 descendant fonts.
Furthermore, registry and ordering values in its CIDSystemInfo dictionary aren’t standard, which is why Adobe Acrobat is also unable to extract the document text completely. (See: Acro_convert_error.jpg (12.1 KB)) Unfortunately the part of text cannot be extracted correctly from the document and it is not a bug of Aspose.Pdf but flaw of source document.
In case of any further assistance, please feel free to let us know.