Create a Packed Level Actor with one or a few StaticMesh actors, the pivot point being Center Min Z
Create another Packed Level Actor containing an instance of the one created step 1 (can be alone or with other objects), the pivot is still Center Min Z
See the new Packed Level Actor pivot is now lower than it should
Optional: If the new Packed Level Actor level is loaded and inner Packed Level Actor is selected and bounds displayed, it seems to explain why the pivot is too low
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