[Solved] HDRP 7.3.1 - no shadow caster culling optimization present any more?

since unity 2017 shadow casters where dropped in higher shadow cascades if they were fully covered in a lower cascade already (more or less) using the built in rp. unity always was very conservative regarding this but testing HDRP 7.3.1. is seems to have been fully dropped which is a huge performance degression imho.

as you can see: the small cube is already fully covered in cascade 2. so it might appear in cascade 3 as well (conservative, ok). but it is also rendered in cascade 4!
i simply can not believe that such a simple optimization proposed by the former stingray team fully got overseen.
or do i miss something here?

 

turned out that unity 2019.3.5 and HDRP does even more conservative shadow caster culling compared to unity 2018.4.lts and built in RP.