Action-Aliases `salt-local state.highstate` doesn't apply highstate

[nzlosh]

When the salt.local action is called from the command line providing module=state.highstate and target, the high state is applied to the target machine. If the action is trigger via the action-alias, the result appears to apply the configuration changes but none are observred on the target machine. It seems like it's running with test=true.

salt.local from action-alias

id: 5defab2838b7e592a6f1332c
status: succeeded (5s elapsed)
parameters:
  args:
  - '[]'
  module: state.highstate
  target: automate*
result:
  exit_code: 0
  result:

salt.local from cli

id: 5df0064c38b7e592a6f13347
status: succeeded (5s elapsed)
parameters:
  module: state.highstate
  target: automate*
result:
  exit_code: 0
  result:

The only difference I can see between the 2 calls is that arg parameter is passed an empty list. This behaviour has been observed using salt-2018.3.4