Tested with trunk, no custom shaders etc. I'm attaching testcase. TESTCASE
Now about the issue itself. Testcase contains two missions. First will show you two spheres with intensive environment reflections from engine-generated cubemap. What I see there is:
Which means its kinda off! Faces seem to be in place, but it also seems some coordinates are flipped.
There is also a second mission, which is different in only that it uses extrenal cubemap for reflections. It leaves room for my own error, but it is something to look into.
Now what is wrong here? Well, the skybox behind the player looks like this:
Notice, how the reflection corresponds to skybox. Normally, if you reflect an image which looks like /, you will get a reflection looking like \. Here both the image and reflection are /. Again, this may or may not be my own fault. First issue is however 100% valid.