Macbook Pro Retina (mid-2014) shutdowns with -128 code
Here is a post suggesting disabling the Thunderbolt Ethernet Driver solves the issue.
Another post suggests the nocrashmbp utility which says 2013-2015 MacBook Pros are susceptible:

The CPU has several power states and voltages.  Some CPUs have become unstable at the extremely low voltage on one of it's cores.   The CPU will sometimes briefly dip into that power state, and if it happens to be on the core wherein it is unstable you will see the “silent” crash.  Screen goes black, a few seconds later it dies completely.  This condition was observed with external test equipment, as well as through internal cpu voltage monitoring.