Hi Joojaa,
Thanks for reply!
A few other friends out of this forim confirmed that have the same issue. How are you making it to work, can you please post. Ma file? Leave the timline to 500 frames and play the scene, sometimes it can go trough all 500 frames and do not show a spike, but it's more evenly to show them. Also in different scales the size of the spikes is different and finally the effect is more obvious on high poly meshes.
We have tried the simple cylinder test from scratch in maya 2013, 2014 and 2015, it's all the same and there is something new on the horizon. When first choose which points to be influenced with the deformer membership editor and then paint the weights and save the scene, on reopen the painted information is lost and the object looks broken, but as soon I import the early saved weightmap it comes back to normal.
In other words when you send the scene to batch render, the result is just as bad like when reopen the scene and have nothing similar to the last state of the scene.
Best,
Niki