Saying Building will collapse when it is on flat terrain

Issue description

I have a Loose dump III sitting on level 2 ground, has sat there for months. The ground immediately along two sides is slightly higher. Storage was placed where the ground rises slighly next to a hill.
Sending excavators to clear down to ground level 2 causes a warning about collapse due to loose ground.
How is that possible when the ground is flat? if i was digging down i could understand it.

Reproduction steps

Loade attached save
click on builing collapse warning and check the ground level

Game version and build number

v0.6.4d b343

Operating system

Windows

Attachments

2024-08-08 bug.save

What is your point? That is a bump not a dip

There doesn't have to be a dip, you can't fill buildings with loose materials from above.

It's just a warning that your building is not on a flat surface. It's clearly not, this is not a bug.