Go to https://en.wikipedia.org/w/index.php?title=User:Neil_Shah-Quinn/Testcase_1&veaction=edit
Reuse citation 1 at the end of the first paragraph. Then, delete the reflist template and replace it with a normal references list.
Now, review your edit. The original citation 1 has disappeared, leaving only the reused citation 1, without any content.
Seen in Firefox 51.0b4.