To replicate:

1. Create a page 'Page One' (target).
2. Create another page 'Page Two' (linking). Create a link to 'Page One' wrapped in {warning} macro.
3. Rename 'Page One' to 'Page One Test'.
4. Refresh 'Page Two'. The link will still refer to 'Page One' not 'Page One Test'. As a result, it will be displayed in red and clicking on it will create a new page called 'Page One' (normal Confluence behaviour).

Removing the {warning} macro causes the links to function correctly.