First excuse my poor english.

Ok. This is what I did.
1. Make a cub with Subdivisions Width 2.
2. Delete the half of faces.
3. Duplicate the half cub and scale X -1.
4. Select both cubs and combine , merge vertex.
5. And try bevel. All faces are gone.
6. Let’s reassign lambert1.  Back to normal....

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Well, it can be a bug…

But try this: Before combine two objects, get reverse the normals of the negative scaled (it haves reversed normals)

necro bug bump…

checked this in Maya2012 sp1 x64/win7/geforce GTX 480
And I get the same result after the bevel applied at once to all edges just as first described.
IF I use the initialShadingGroup’s Lambert.

All is fine if I apply another material before the negative scaled dup combine.

Here is a strange twist…
If I assign a different new material like phong: The object is visible again. And if I change that phong’s type to a Lambert it still is visible!

Now, here is an even stanger twist…
If I then RE-ASSIGN the object BACK to the initialShadingGroups ORIGINAL LAMBERT the object is STILL VISIBLE!!
In fact if I assure the shading network is the same as the original state by cleaning the scene with an “Optimize Scene Size” the object is still visible with it’s original shading group as if nothing was ever fubar?
No Idea why the material change would jumpstart the initialShader to start working again but that is what seems to be happening.

Not that this is an important bug. But jes in case knowledge of as much illuminates a fix for any related bugs. :)

Sounds like the connection to the ShadingGroup node is getting broken.
I don’t have a solution - other than to simply reassign your material.

n8skow [FA]