Enter is a special character. Clipboard text sees this as \r\n, but feeding that one character at a time into SendKeys /AutoIt.Send makes it emit two separate returns. So, this has been broken ever since inter-key delay was added.
Also, see #31 , for some reason Word took a typed \n to mean "go to the next page".
Anyway, collapse \r\n to just \r and it looks like everything is happy.