DOCX Looks Correct in Word but Has Extra Character Spacing in DocuSign

I have a Word template that I populate programmatically using C# and the Open XML SDK. The generated DOCX looks correct when I open it in Microsoft Word. However, when I upload the same DOCX directly to DocuSign and open the document for signing, I notice extra spacing between some characters in two paragraphs. The character spacing appears normal in Microsoft Word but changes when the document is displayed in DocuSign. I have added the screenshot for your reference 

First image: The generated Word document opened in Microsoft Word, where the character spacing appears normal.

Second image: The same document opened in DocuSign for signing, where extra spacing between some characters is visible.

I have also verified the font and character-spacing settings in the Word document, and they appear to be normal. Additionally, if I convert the generated DOCX to PDF using Microsoft Word and then upload the PDF to DocuSign, the spacing issue does not occur.

Could you please help me understand why this is happening? Is this related to how DocuSign renders or converts DOCX documents when they are opened for signing? Is there any recommended solution or formatting change to prevent the extra character spacing when using DOCX directly?