Algodoo

funnily this has the same thumbnail as the previous scene

Hi I'm Alxe, I have searching what could cause this.
In my investigation I have found that if two proyects are shared nearly at the same time the cache of the server won't be empty, so it recycles the thumbnail, you can edit the escene to try to force a new thumbnail.
This is the first time that something like this happened to me this thing and the near perfect sincronization in the upload

your theory is very good