OffsetOnSide fails

[andrewheumann]

{"discriminator":"ThickenedPolyline","polyline":{"discriminator":"Elements.Geometry.Polyline","Vertices":[{"X":48.257549035747004,"Y":23.780628528982568,"Z":0.0},{"X":48.257549035747004,"Y":49.757450994516574,"Z":0.0},{"X":126.21709087411392,"Y":49.757450994516574,"Z":0.0},{"X":126.21709087411392,"Y":23.028820612771966,"Z":0.0},{"X":123.4214786028532,"Y":23.028820612771966,"Z":0.0},{"X":123.4214786028532,"Y":23.780628528982568,"Z":0.0},{"X":48.25111595094629,"Y":23.780628528982568,"Z":0.0}]},"width":1.5,"flip":false,"leftWidth":0.0,"rightWidth":1.5}

For the above ThickenedPolyline (as "corridorPolyline"), calling corridorPolyline.Polyline.OffsetOnSide(corridorPolyline.Width, corridorPolyline.Flip); throws an exception, complaining about intersecting segments of a polyline.