Steps to replicate the issue (include links if applicable):

• Start editing an article in the visual editor while logged out.
• Open the article on another device (or browser profile) and save an edit there (does not matter if logged in or not) to cause an edit conflict.
• In the editor from step 1, make sure to edit the same paragraph as in step 2. Then click "Publish changes..." and again "Publish changes".
• In the edit conflict warning box that appears, click "Resolve conflict".

What happens?:
The editor switches to a classic code editor page which is titled "Edit conflict: /.../", however there is no sign of the changes made while in the visual editor. Clicking "Show changes" returns "(No difference)".

What should have happened instead?:
Options to resolve the edit conflict should appear. If I click "Resolve conflict" while logged in, I am offered to choose paragraph-by-paragraph which revision to save.

Other information (browser name/version, screenshots, etc.):
Experienced and successfully reproduced multiple times today on the Slovene Wikipedia.