What is your end voltage when it does cutoff?

In addition to what others have said, try setting the cutoff to 2.8 a cell. The LVC on the hw and many others seems to be off or inaccurate. I have mine at 2.8 a cell and it cuts off at 6.3v on a 2s pack or roughly 3.1v per cell. I have had 4 or so of these esc's and all have been the same. Very rarely do I run a pack to cutoff but if I do in practice, this is what I have always found. Hope this helps