Terrain-Flattening output dependent on the subset size

Currently we are busying with the ETAD support work. After that, we will address the issues with terrain flattening operator.

There is new discussion about this on the forum - can we expedite the resolution?

It seems you were looking into this issue back in 2021. What was the outcome? Is this solved? If there are some differences in the terrain flattening when only subset is selected and the difference is negligible maybe it would be worth adding a note in the help file describing this issue

I encounter the same type of issue with calibration:
It seems depends to the subset size.