Unwanted text duplication with sortableJS

[raphaelriehl]

Hello,
I want to create a block in which the elements are sortable.
The problem is that when I sort the elements with sortableJS, their content is duplicated and added after my block.
Here is a video to explain :

editorjs-and-sortablejs.mp4

And a Codepen link that reproduces the problem :
https://codepen.io/raphaelriehl/pen/QWoxqaE

The purpose of this plugin is to create a photo gallery with the possibility of reordering photos.

How to solve this problem ?

[raphaelriehl]

I updated my first post to better understand how to reproduce the bug (video + codepen).
If someone has an idea ?

[SlavaDidenko]

The same problem, who has a solution, please share.

[raphaelriehl]

@SlavaDidenko I submitted a pull request which corrects the problem but I don't know if it will be validated and if it doesn't create a regression.
You can test the solution if you want : 0d1d53a