Retaining Wall Threatening Collapse when it should not

Issue description

Retaining wall where the top is at ground level is threatening to collapse. Really?

Reproduction steps

Load attached Save
Look for said wall in the Coal Mine

Game version and build number

v0.5.5 b246

Operating system

Windows

Attachments

Twelfth.save

Without any information or pictures there is no way to help you.
Make sure the red stripes are not visible when placing the retaining walls, as shown in the Message Center about retaining walls.