The invisible hand
Whenever a scan is finished, Gauntlet performs smart operations in the database in order to intelligently classify vulnerabilities as fixed or resurged. Those operations save you time and even give you security insights.
After each scan Gauntlet computes which vulnerabilities weren't not present and consider them fixed. So the best way to pragmatically identify whether a vulnerability is fixed is to run a scan again and let Gauntlet smart operations work for you.
It's very important to track whether vulnerabilities were previously fixed but were identified again. Gauntlet mark them as 'Resurged' and even keep track of how many times those vulnerabilities resurged. It's an important indicator of lack of developer training, lack of unit tests or lack of any other security measure that let it happen again.