MeshSkinning is slow on the Surface Pro. Is this a bug?

It seems this issue may have been around for a while and may have been fixed in some form previously, but using the current latest version of Unity 4 (4.6.5p4) I see noticeable performance spikes in the profiler when re-enabling disabled SkinnedMeshRenderers on particular Windows Store devices.

The issue seems similar to this one (marked as 'fixed in future release'): meshskinning-dot-prepare-is-slow-when-toggling-renderers-and-gpu-skinning-is-enabled though for me it is only happening on a specific device.

From my testing I know the following:

• Only observed as an issue on the Surface Pro (v1).

• Doesn't occur on the less powerful Surface RT (v1).

• Doesn't occur in editor and on other platforms.

• Doesn't occur if I disable GPU Skinning in Windows Store player settings.

• Spike occurs when I re-enable one or more SkinnedMeshRenderers after disabling them for a second or two.

• In the profiler the cause appears to be: MeshSkinning.Update() >> MeshSkinning.Prepare, with Mesh.CreateVBO getting a mention too.

• There are usually two spikes in quick succession after the renderer component is re-enabled (see attached image).

  

Could this be the old Unity bug resurfaced? And when will the fix for the linked issue be released so I can test it?