This primarily affects Wikivoyage, as two subsections of the same page might have the same name, something like:

'''India''' is a country in southeast Andalasia which primarily manufactures India ink.

Get in

By elephant

• Rent an elephant in the neighbouring country of <s>Pachyderm</s> [[Pakistan]].

Get around

By elephant

• Just ring +91-800-RENT-A-JUMBO and an elephant will be delivered to you.

See

• Elephants. If you find an albino, bring her back to Ste. Monique (Québec) as a pet and name her Mirabel. Beautiful name...

Internally, the 'id=' HTML tag for 'Get in - By elephant' is [[India#By elephant]] and 'Get around - By elephant' is tagged as [[India#By elephant 2]]. The [edit source] links all edit the page by section number, not section name, so should not be affected by duplicate section naming (and is OK unless someone just added a section since the page was last refreshed).

Save the edit, though, and the display afterward returns to the normal reading mode - supposedly at the section last edited. This works, unless two subsections have the same name. Edit "Get around - By elephant", hit the [save] button and the display returns to [[India#By elephant]] instead of [[India#By elephant 2]].

Not hugely noticeable (as the edit does get made correctly) but not quite what the user was expecting.