[Reg 6.7 -> 6.9] QJSEngine: created JavaScript objects does not have function hasOwnProperty

We are using the QJSEngine in one of our projects. There, we injected a C++ object to the JavaScript global scope. This object has a property returning a QVariant. 

The problem is that in the JavaScript world this property does not return a "regular" JavaScript object - it does not have a function hasOwnProperty, which every regular JavaScript object has. The conversion itself seems to be working - the properties are all available...

With Qt 6.7.3 it was working fine, but with Qt 6.9.0 it is broken.