Smart Device Groups - Filter/Display Error?

Hello,

we have a strange problem with variables in Smart Device Groups.

For example, we filter for outdated iOS versions:
Criteria: iOS Version is not 15.4.1 and Mobile Device Group member of All Managed iPads and Model Identifier is not iPad 4,2 (There is no iOS 15.x for the old iPads).

And in the result list I always have some entries with iOS version 15.4.1 and older versions.

But why are the devices with the current version 15.4.1 displayed?

Thanks in advance and many greetings from Germany

Sebastian