Stretched text in paragraph when content is justified

Hi,
Trying to merge two documents by importing the section, in the merged document the last line of the paragraph is getting stretched. The text in the paragraph is justified and not used shift+enter. Attached the zip file which has input files, outputfile and the code used.
Note: the text is not stretched in the input file(before merged)
Expected: the line should not be stretched.
Thanks!
AsposeIssue.zip (6.2 MB)

@kaushlendu.choudhary The problem occurs because your document is optimized for old version of MS Word. You can use the following code to resolve this:

Document doc1 = new Document(@"C:\Temp\test3.docx");
Document doc2 = new Document(@"C:\Temp\test4.docx");
doc1.AppendDocument(doc2, ImportFormatMode.KeepSourceFormatting);
// Optimize for MS Word 2019.
doc1.CompatibilityOptions.OptimizeFor(MsWordVersion.Word2019);
doc1.Save(@"C:\Temp\out.docx");