Terrain's Flatten tool is inaccurate

I’m posting this in here because i don’t have acces to #bug-reports and i still did not understand how do i get acces to it

Does anyone know why is this happening or something? This bug has been in here for a long time already, because i sometimes had this happen before too.

You need to flatten on a fixed plane.

like what @RMofSBI said, you need to flatten it on a fixed plane. That means that the grid has to touch the terrain that the blue orb is touching.

i tried so much and it just refused to flatten even though it was touching

Possibly that the terrain is too close to the original flattened terrain that it cannot detect. Try growing concrete then smoothing and flattening it.

Use the Top mode rather than the Center or Bottom mode.

still didnt work but i did it by part to terrain and by making a part
but even tho i got the solution, this shouldn’t happen

i tried every mode and it just refused to work