Received incorrect faces while loading IGES

chrono
pload ALL
NewDocument d XCAF
ReadIges d "e:/old file/e/test/false_circle2.igs"
DFBrowse d
XShow d
vsetdispmode 1
vfit

When using the above script to load IGES, the small facets in the box become circular surfaces (missing the small facet part), and loading in CAD Assistant is not a problem,
Could you please help me understand the reason and what parameters need to be set
Version 7.8
Import code

// Read
IGESCAFControl_Reader reader;
reader.SetReadVisible(true);
IFSelect_ReturnStatus status = reader.ReadFile(filename);
Handle(XCAFApp_Application) anApp = XCAFApp_Application::GetApplication();
anApp->NewDocument(DOCUMENT_FORMAT, m_document);
if (IFSelect_RetDone != status || !reader.Transfer(m_document, aPS.Next(50)))
return false;