Wrong tessellation for pipe-alike geometries when setting "isRelative" parameter to TRUE in "BRepMesh_IncrementalMesh"


I'm developing an application that imports a STEP file, tessellates shapes in the STEP file, and exports an X3D file.
I'm using OCCT 7.5.0.

I've got the wrong tessellation for pipe-alike geometries as shown in the attached PNG file.
The STEP file shown in the picture can be downloaded from the link: https://grabcad.com/library/gtcp85-98d-1
I failed to directly upload the STEP file because it is too big (over 100 MB). I'm sorry for the inconvenience.

I tessellated each shape by using "BRepMesh_IncrementalMesh" while setting "isRelative" to "TRUE".
The angular deflection was set to the default value.

Is it a bug?

Thank you!