Mesh.CreateVBO causing stutters with Metal renderer?

Hello. I'm just putting together a new build of my game and I upgraded Unity from 5.1.1p3 to 5.1.3f1 and noticed I was getting severe performance dips on A7 and A8 devices. I made a profiler build and it showed some very noticeable spikes which turned out to be Mesh.CreateVBO taking ~20ms and up on some frames:
My iPad 2 wasn't stuttering so I thought it might be due to Metal. I tried turning off that renderer in the player settings, and that solved the problem:

(those screenshots are the same area of the game on the same device, Metal above, GL ES 2.0 below, 5.1.3f1)

I'll file a bug, but I just thought I'd post here in case anyone else is having the same issue, and check if it's a known problem before I go and isolate a test case and such?

 

No one reply? really important

 

What is the bug number? I'm facing the same issue

 

I can't find an email so I don't think I did file a bug in the end I'm afraid. Sorry about that

 

Just in case it's of any use, my game used a lot of 2D Toolkit sprites, so it was doing a very large amount of dynamic batching, and that might be involved with this problem.

 

I've tried turning of dynamic batching in build settings, and that's not work.
The Mesh.CreatVBO happened when I activate an effect with a few quad meshes, every time the mesh renderer is enabled to be more specific.