Modeling Algorithms - Use of BRepAlgoAPI_Defeaturing class corrupts model topology

Using the attached STEP file (zipped), 'housing-01.stp':
1) Instantiate a defeaturing object using BRepAlgoAPI_Defeaturing defeature;
2) Set the shape using defeature.SetShape(..) (note that the model is comprised of a single shape)
3) Disable both parallel processing and fill history modes:
            defeature.SetRunParallel(false);
            defeature.SetToFillHistory(false);
4) Select the surfaces as indicated in red in the attached image, 'Attachment 1 (PNG)' and add each using the method 'AddFaceToRemove()'. Note that the chamfers for all the bolt holes on the lower plate are to be selected.
5) Perform the defeaturing using the "Build()" method.

The resulting topology is shown to the right in the same image. Note the changes in the topology as indicated by the yellow highlighting between the original and defeatured models. The topology has been altered though no defeaturing was indicated in these areas.