During VSA installation process (for example during patch installation), the add-on module list shows Antivirus/Antimalware module "version installed" as 18.104.22.168, even though the installed version of VSA and other modules is 9.1.
This is a cosmetic defect introduced in a recent patch release.
Installation of patch 22.214.171.124 will resolve the issue. After that, the module will be correctly reported as having version 126.96.36.199.
Kaseya VSA R9.1