Good morning. On the condition that your font remains the same, your issue is a bit perplexing, assuming the font remains identical between the two documents. I would try choosing a paragraph that adds a line in the new document and:

1. Select it in the source doc and use Paste Special/Unformatted text to bring it into the new doc.

2. Select it in the source doc, Paste it into the new doc, select it there and, holding Ctrl down, press Spacebar and Q in succession, to clear paragraph and character formats.

Does either of these make any difference?

Best,
Ulo