Can't believe I didn't think of this earlier.
Raised the elevation of the stairs by .001 Meter.

Have a desk partially under stairs.
Perfect in 3D.
In 2D it appears that the desk is over the stairs.
Have noticed the same thing when putting chairs under a table.
How do I fix this?
Thanx, Alan

Started a project.
Unable to get extra furniture (roof) with android browser.
Installed Firefox.
Unable to open project in Firefox.