Handing over to you to investigate, Jesse.  I believe Omri has a bit of insight into how these pages are put together.

It appears the SmartLock URL contains the page's friendly name and build info. For example, on my Eve:
https://support.google.com/chromebook/?p=smart_lock&b=eve-signed-mpkeys

After some digging around in Redwood, it appears the friendly page name for the desired target page is now 'easy_unlock' and not 'smart_lock'

Testing this updated URL using the same hyperlink structure as the original works: 
https://support.google.com/chromebook/?p=easy_unlock&b=eve-signed-mpkeys

James, can you assign this to someone on the team to make the fix? I see a handful of areas in CS where "p=smart_lock" needs to be updated.

After chatting with James, we've decided to instead reach out to the Help Center team to revert this change on their end.

I'll take ownership of this issue again and update this bug when the changes have been carried out.

Issue is being tracked in https://b.corp.google.com/issues/80305852

This issue has been fixed.