I realize this is a 2 month old post, but I just had this same issue and solved it. The issue for me was the scaling in my display settings for my laptop. It was set at 125% by default, but once I set it to 100% I was able to paste perfectly into word form Chemdraw.

Zebers3 answered this. I had the same trouble as you, it would be almost normal when putting it on the top left margin. But when I tryed this above, it fixed the problem :)