Copy/paste from https://www.mediawiki.org/w/index.php?title=Topic:Tnc1xizxa9e3tuow&action=history :

When two references switch positions their numbering is shown incorrectly in the preview.

Steps to reproduce:

Go to an article with an reference, e.g.Extension:Scribunto (1) and enter edit mode
Cut (e.g. copy) reference 1 from its location, and paste it on the location of reference 2
Cut (e.g. copy) reference 2 from its location, and paste it on the location of reference 1,
Follow the rest of the steps in the first post
Expected

The preview shows reference "[1]" for the first reference, and reference "[2]" for the second

Actual output

The preview shows reference "[2]" for the first reference, and reference "[1]" for the second

Notes:This is pretty confusing with two references, so imagine with 5 or more references being moved around. It might also be useful to add some sort of note in the sidebar and perhaps include a hover that displays the content of the references.