Offseting to the inside of a pline does not trim some of the corners

Rhino Rhino for Windows
1

Some of the corners do not trim even though Trim is on.

offset example
offset example2480×3507 62.9 KB

2

When trim is on the offset command still creates triangles in corners when offset to the interior (but good when offset to exterior)

offset example
offset example2480×3507 62.9 KB

3

Could I have this 3dm file? Thanks.

4

houseexample.3dm (50.1 KB)

5

It is not a coplanar curve, Offset will be fine after make it as a coplanar curve via SetPt

6

Thank you