Why the candidate source names is unchanged at candidate profile level?

Summary:

There is candidate already present in system, with the following source information at candidate profile under candidate search page of hiring.

Source: Agency

Source Medium: Candidate Created Manually

Now, same candidate applied to job opening via external career site. And source information at the job application level for same candidate becomes:

Source: External Career Site

Source Medium: Career Site

Now after this when recruiter checked the same candidate in candidate search page the source information was not updated with external career site source.

Why the source and source medium is not updated at candidate profile level when same candidate applied to job opening via career site.