Touching on your point of running a full scan and the findings still appearing, was this the button located under the asset or remediation project to scan now? If so, I believe that functionality tells a compatible scan engine to rescan the host, however, a scan engine would enumerate things such as open ports, banner grabbing for vulnerable versions, etc.
The browser vulnerability finding originates from the Rapid7 agent. There is currently no functionality to tell the agent to immediately rescan a host for validation purposes. However, I believe from a recent post, Rapid7 might be introducing this functionality.
Link to that post: InsightVM On Demand Agent Assessment