Export causes inverted scaling

Hello Forum,
there are a number of threads regarding this topic but sadly I could not find a solution/answer that applies to my situation.

Speaking of my situation: This is my application and the apartment node is the root object of the scene with the scaling of (1,1,1). So far so good…

When setting useRightHandedSystem to false then the export looks correct (rotation/scaling/lighting) but the scaling factors are inverted. On the Root Level the Z Axis is inverted and on the apartment Level the Y Axis is inverted (as far as i understand the other threads, this is the expected behaviour)

Now I tried to set useRightHandSystem = true to fix the inverted scaling (as was proposed in some of the threads on this topic). Now the Root node is still inverted on the Z Axis but the apartment node is no longer inverted on the Y Axis. So theoretically I can now also flip the Root Scaling back to positive manually and end up with a model that is rotated/scaled in the same way as seen in my application. But now the lighting of my scene is off so i am afraid that i got the whole thing entirely wrong…

(this is the export with useRightHandSystem = true and the root Node Z Scale flipped back to positive)

I am aware that this is a lot to take in. Therefore my first and possibly only question is this:
Is this once again the expected behaviour or could there be something wrong?

cc @bghgary

The export has a bunch of issues. We will hopefully start tackling them in the coming months. Can you share a repro of your scenario?