About [[MediaWiki:Wikibase-error-ui-edit-conflict/en]]
Currently this message is: ‘There is an edit conflict. Please reload and save again.’
The documentation adds: ‘Note that the default message says the user shall "reload and save", but after a reload the content that should be saved will be lost.’
The documentation describes a fatal flaw in the error message: the user is directed to completely lose their edit without being warned that this is about to happen. This flaw should not be documented; it should be fixed. Either the error message should direct the user to copy and paste their edit elsewhere before reloading the page, or the software should be fixed so the edit isn't lost in the first place.
If you're pointing out an issue in MediaWiki that cannot be resolved in the i18n or L10n area, please create a report in https://bugzilla.wikimedia.org.