salt.states.augeas.change: New XML elements created when trying to add attributes

Description of Issue/Question

When trying to add attributes to a newly created element in XML using augeas.change and the example shown here https://github.com/hercules-team/augeas/issues/175#issuecomment-286603937 , multiple elements are created instead

Setup

xml file at /tmp/test.xml

<host>
   <server name="one" attr1="dog" attr2="brown"/>
   <server name="two"/>
</host>

Steps to Reproduce Issue

SLS file:

add test:
  augeas.change:
    - lens: xml.lns
    - context: /files/tmp/test.xml
    - changes:
      - set host/server[last()+1]/#attribute/name 'new_server'
      - set host/server[#attribute/name="new_server"] '#empty'
      - set host/server[#attribute/name="new_server"]/#attribute/attr1 'cat'
      - set host/server[#attribute/name="new_server"]/#attribute/attr2 'dog'

result:

<host>
   <server name="one" attr1="dog" attr2="brown"/>
   <server name="two"/>
<server name="new_server"></server>
<server/>
<server attr1="cat"></server>
<server attr2="dog"></server>
</host>

desired result:

<host>
   <server name="one" attr1="dog" attr2="brown"/>
   <server name="two"/>
<server name="new_server" attr1="cat" attr2="dog"/>
</host>

augtool commands that produce the desired result:

transform Xml.lns incl /tmp/test.xml
load
set /augeas/context /files/tmp/test.xml
set host/server[last()+1]/#attribute/name new_server
set host/server[#attribute/name="new_server"] #empty
set host/server[#attribute/name="new_server"]/#attribute/attr1 cat
set host/server[#attribute/name="new_server"]/#attribute/attr2 dog
save

Note: This works

add test:
  augeas.change:
    - lens: xml.lns
    - context: /files/tmp/test.xml
    - changes:
      - set host/server[last()+1]/#attribute/name 'new_server'
      - set host/server[last()] '#empty'
      - set host/server[last()]/#attribute/attr1 'cat'
      - set host/server[last()]/#attribute/attr2 'dog'

Versions Report

Salt Version:
           Salt: 2017.7.1

Dependency Versions:
           cffi: 1.5.2
       cherrypy: Not Installed
       dateutil: 2.4.2
      docker-py: Not Installed
          gitdb: 0.6.4
      gitpython: 1.0.1
          ioflo: Not Installed
         Jinja2: 2.8
        libgit2: 0.24.0
        libnacl: Not Installed
       M2Crypto: Not Installed
           Mako: 1.0.3
   msgpack-pure: Not Installed
 msgpack-python: 0.4.6
   mysql-python: Not Installed
      pycparser: 2.14
       pycrypto: 2.6.1
   pycryptodome: Not Installed
         pygit2: 0.24.0
         Python: 2.7.12 (default, Nov 19 2016, 06:48:10)
   python-gnupg: Not Installed
         PyYAML: 3.11
          PyZMQ: 15.2.0
           RAET: Not Installed
          smmap: 0.9.0
        timelib: Not Installed
        Tornado: 4.2.1
            ZMQ: 4.1.4

System Versions:
           dist: Ubuntu 16.04 xenial
         locale: UTF-8
        machine: x86_64
        release: 4.4.0-96-generic
         system: Linux
        version: Ubuntu 16.04 xenial

Start by reproducing the SLS example with augeas.change, xml.lns, and /tmp/test.xml, then compare its result with the listed augtool commands. Trace the Salt augeas.change path and its handling of sequential XML node changes; done means the SLS produces one new server element with all three attributes.