I get exactly the same flickering problem with parts of GE 3d building models.

In every instance I've found, it occurs on those building models with an internal structure. Where the internal structure contains at least one flickering (multiple face) polygon.

It's as if the 3d renderer update from GEv3 to GEv4 caused internal modelling errors to present themselves externally for some users. Like having X-Ray vision.

As far as I can tell everything on my system is up to date:

Clean GE4 beta2 install

Latest video driver - ATI catalyst 6.6, DirextX 9.0c + every Windows XP Update

Both GE caches cleared and increased in size.

Makes no difference whether I use OpenGL or Directx.