Steps to replicate the issue:

• Disable "Show preview without reloading the page" in Preferences
• Click "Show preview" or "Show changes" while editing a page

or

• Enable "Prompt me when entering a blank edit summary (or the default undo summary)" in Preferences
• Edit a page and save without entering a summary
• You are navigated to "Reminder: You have not provided an edit summary. If you click 'Publish changes' again, your edit will be published without one."

What happens?:
"Changes recovered" popup appears.

What should have happened instead?:
The popup does not appear.

Other information:
Same should apply to probably most situations in which the edit form is submitted in a POST request (edit conflict, expired token, page deleted or created, logged out warning, etc.).