Had a bit of a play and if you turn mask value 1 off (i.e. leave just 2+4) then all is good.
Likewise turn transparency off in 3D window settings all is good.
Seems like mask 1 is forcing the object to think it is transparent?
Barry.
Versions 6.5 to 22
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision M6800 - i7 4700MQ @ 2.40GHz, 16GB RAM, AMD FirePro M6100 (2GB), Windows 7 64bit