"Clear History and Website Data" did not clear the history. The issue was addressed with improved data deletion. This issue is fixed in macOS Big Sur 11.1, Security Update 2020-001 Catalina, Security Update 2020-007 Mojave, iOS 14.3 and iPadOS 14.3, tvOS 14.3. A user may be unable to fully delete browsing history.
Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:NI:LA:N3.3/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N