Hi Abhijeet,
Thank you for being patient.
Our development team has completed the work on your issue (WORDSNET-6908) and has come to a conclusion that this issue and the undesired behaviour you're observing is actually not a bug in Aspose.Words. So, we've closed this issue as 'Not a Bug'.
The problem occurs because the input .doc document contains highlights which causes the highlight color appear in output document. In this case, Aspose.Words mimics the behaviour of Microsoft Word i.e. please open the original document and save it as web page ( save as=>other formats => choose "Web Page" as format) and you will notice that output produced by Microsoft Word does also contain the highlights.
To overcome this problem, you just need to delete the highlights manually from the original document. The simplest solution is: select all text in the document (Crtl + A) and then set "Text Highlight Color" to "No Color".
If we can help you with anything else, please feel free to ask.
Best regards,