Documents merge issue

Hello experts,

I'm using below code to merge multiple documents. But, after merging, I see some issues in the merged document. 

 public static void MergeDocuments(List<string> documentPaths, string outputFile)
        {
            if (System.IO.File.Exists(outputFile))
                System.IO.File.Delete(outputFile);

            string firstDoc = documentPaths.First();
            System.IO.File.Copy(firstDoc, outputFile);

            documentPaths.RemoveAt(0);

            using (WordprocessingDocument myDoc = WordprocessingDocument.Open(outputFile, true))
            {
                foreach (var documentPath in documentPaths)
                {
                    string altChunkId = string.Format("AltChunkId{0}", Guid.NewGuid().ToString());
                    MainDocumentPart mainPart = myDoc.MainDocumentPart;

                    AlternativeFormatImportPart chunk = mainPart.AddAlternativeFormatImportPart(
                        AlternativeFormatImportPartType.WordprocessingML, altChunkId);
                    using (FileStream fileStream = File.Open(documentPath, FileMode.Open))
                        chunk.FeedData(fileStream);
                    AltChunk altChunk = new AltChunk();
                    altChunk.Id = altChunkId;

                    Paragraph para = new Paragraph(new Run((new Break() { Type = BreakValues.Page })));

                    mainPart.Document.Body.InsertAfter(para, mainPart.Document.Body.LastChild);
                    mainPart.Document.Body.InsertAfter(altChunk, mainPart.Document.Body.LastChild);
                    mainPart.Document.Save();
                }
            }
        }

The second document I merge has some abnormal line spacing issues in the merged document. It adds extra space after each of the paragraphs. Even the lines in a table also get space after them. If you kindly review the documents, you will notice the issues.

I have uploaded 3 documents in the onedrive account.

Doc 1: https://1drv.ms/w/s!AmifSn8Lhbgbg24v61BIYPjJvTt-

Doc 2: https://1drv.ms/w/s!AmifSn8Lhbgbg2wv61BIYPjJvTt-

Merged: https://1drv.ms/w/s!AmifSn8Lhbgbg20v61BIYPjJvTt-

I have merged "Doc 1.docx" and "Doc 2.docx". The output is merged.docx. You can run below code to merge them.

static void Main()
        {
            var list = new List<string>();
            list.Add(@"C:\temp\doc 1.docx");
            list.Add(@"C:\temp\doc 2.docx");

            string output = @"C:\temp\merged.docx";
            MergeDocuments(list, output);
        }

Any help on solving the issues will be highly appreciated.

Thanks in advance.