Renaming parent leads to redirect loop when accessing child location's old URL in the front office. Clearing the persistence cache afterwards fixes the issue.
Most probably this is due to the incorrect cache clearing in the UrlAliasHandler::clearLocation() method (https://github.com/ezsystems/ezpublish-kernel/blob/24e938f7c8cd6a045b987745d5d7194ebf0bc5e3/eZ/Publish/Core/Persistence/Cache/UrlAliasHandler.php#L327).

Steps to reproduce

1. Create new eZ Platform installation.
2. Create new container object (e.g. Folder "My Folder").
3. Create new object inside this container (e.g. Image "My Image").
4. Navigate to both of them in the front office (http://example.com/My-Folder and http://example.com/My-Folder/My-Image).
5. Rename "My Folder" to "My Folder Modified".
6. Reload child's old URL in the frontoffice (e.g. http://example.com/My-Folder/My-Image).
7. Observe infinite redirect loop.
8. Clear caches.
9. Reload child's old URL in the frontoffice again (e.g. http://example.com/My-Folder/My-Image).
10. Get redirected to new URL (e.g. http://example.com/My-Folder-Modified/My-Image).

Navigating to the container Content Object in the frontoffice (http://example.com/My-Folder) in step 4 is important, as without that I wasn't able to reproduce the issue.