Sorry to hear you are having trouble with aligning both the lines in XD. I am able to achieve it by manually drag and dropping the lines on each other. Is that the only file you are having trouble with? If possible, could you please try to share the file with me over a private message so that I can test at my end? You may upload the file to a shared location such as Creative Cloud or Dropbox and share the url with me.
Note: Please share the url of the post for reference over a PM.