Apple is adding a new update type to macOS called Rapid Security Responses. These updates change the build version, but not the OS version reported. Instead, the new ProductVersionExtra (sw_vers) and SupplementalOSVersionExtra (MDM query) keys are returned to denote a specific supplemental version only when a RSR is installed. If no RSR is installed the key is not present. Similarly, when using MDM query (simulated with /usr/libexec/mdmclient QueryDeviceInformation) BuildVersion is unchanged, but SupplementalBuildVersion has the correct RSR build.

$ sw_vers
ProductName: macOS
ProductVersion: 13.3
ProductVersionExtra: (a)
BuildVersion: 22E7752300f

$ /usr/libexec/mdmclient QueryDeviceInformation
{
  BuildVersion = 22E5230e;
  OSVersion = "13.3";
  SupplementalBuildVersion = 22E7752300f;
  SupplementalOSVersionExtra = "(a)";
};

https://support.apple.com/guide/deployment/rapid-security-responses-dep93ff7ea78/web

Please update SimpleMDM to report on installed RSR version and build when present.