Export closed polyline in *.wmf format will exploded in Rhino7&Rhino8

Hi, if I want to export closed rhino polycurve to powerpoint, I can export *.wmf (Windows Metafiles) file to powerpoint and press Ctrl+Shift+G in ppt to get a ppt-available shape.
in Rhino 5 it works fine.
But in Rhino 7&8, when I import *.wmf files using PowerPoint, the resulting graphics appear as exploded line segments instead of closed geometric shapes. Is this a bug? Below are WMF files exported from different versions of Rhino for reference.
ClosedPolyCrv_RH5.WMF (826 Bytes)
ClosedPolyCrv_RH8.WMF (1.4 KB)