A modified version of the reformstudios file described here: http://reformstudios.com/2018/08/15/shotgun-bootstrapping-and-deadline/

GlobalJobPreLoad.py

from System.IO import *
from Deadline.Events import *
from Deadline.Scripting import *

import os

def set_slave_specific_shotgun_home_path(deadlinePlugin):
    '''
    In situations where you have multiple deadline Slaves on a single rendernode
    Shotgun may fail to bootstrap a pipelineconfig if more than one slave
    attempts to bootstrap at the same time. This is because by default each
    slave will use the same location to store it's shotgun pipeline configuration so
    when more than one slave is bootstrapping, there may be two processes attempting to
    copy files to the same location at the same time, thus causing an error.

    Setting a slave-specific directory per slave prevents this clash from occurring.

    :param deadlinePlugin: The deadlinePlugin class passed from __main__
    :return: None
    '''
    deadlinePlugin.LogInfo(". Setting-up environment")
    slavename = deadlinePlugin.GetSlaveName()
    threadnumber = deadlinePlugin.GetThreadNumber()
    deadlinePlugin.SetProcessEnvironmentVariable("DEADLINE_SLAVENAME", slavename)
    SHOTGUN_HOME = os.path.join('C:\\', 'studio','shotgun','cache',slavename,str(threadnumber))
    deadlinePlugin.LogInfo(". setting SHOTGUN_HOME : %s" % SHOTGUN_HOME)
    deadlinePlugin.SetProcessEnvironmentVariable("SHOTGUN_HOME", SHOTGUN_HOME)

def __main__(deadlinePlugin):

    # Set SHOTGUN_HOME environment variable to slave-specific location
    set_slave_specific_shotgun_home_path(deadlinePlugin)