'contact' page doesn't trigger the 404 handler

The Google Search Console showed me “Not found (404)” for the page

https://1der1.com/contact

Our valid contact page is

https://1der1.com/pages/contact-us

We have written a 404 handler using the 404.liquid template, which would redirect to the valid page.

However, the “contact” handle is unique: It doesn’t trigger the 404.liquid template.