After syncing your scanner data into Kenna, there may be a discrepancy between the vulnerability count you are seeing in your scanner compared with the vulnerability count you are seeing in your Kenna instance. This is due to the fact that the number of vulnerabilities in Kenna is based on the number of identified CVEs on an asset. which is an industry standard of tracking vulnerabilities. Scanners may use a different approach.
You can read more about the Common Vulnerabilities and Exposures standard at MITRE.