mine.get works in command line but not inside orchestrator SLS

Description
I want to loop on a list of minions inside an orchestration SLS file, targeting them with a pillar role. Salt mine is defined inside a dedicated pillar.

Setup
mine pillar:

mine_functions:
  grains.item:
    - id

Orchestration SLS test file:

{% set groups = ['db','back','front'] %}
{% for group in groups %}
{% set routes = pillar['netflow']['routes'][group] %}
{% for route in routes %}
{% set targets = salt['mine.get'](tgt='role:{{ route[0] }}', fun='grains.item', tgt_type='pillar', exclude_minion=true).items() | list %}
Test {{ group }} {{ route }}:
  cmd.run:
    - name: echo "targets={{ targets }}"
{% endfor %}
{% endfor %}

The routes variable is retrieved from the netflow pillar:

netflow:
  timeout: 3
  routes:
    front:
      - [ 'back', 'tcp', 22 ]
      - [ 'db', 'tcp', 1521 ]
    back:
      - [ 'front', 'tcp', 80 ]
      - [ 'db', 'tcp', 1521 ]
    db:
      - [ 'db', 'tcp', 1521 ]

Minion role pillars:

minion1 has role: 'db'
minion2 and minion4 have role: 'back'
minion3 has role: 'front'

Steps to Reproduce the behavior
After refreshing pillars and updating salt mine, a cache.mine command returns the correct result:

# salt-run cache.mine
minion1:
    ----------
    grains.item:
        ----------
        id:
            minion1
minion2:
    ----------
    grains.item:
        ----------
        id:
            minion2
minion3:
    ----------
    grains.item:
        ----------
        id:
            minion3
minion4:
    ----------
    grains.item:
        ----------
        id:
            minion4

When targeting the two minions having a role of 'back', the runner command line from the master gives the expected result:

# salt-run mine.get tgt='role:back' fun='grains.item' tgt_type='pillar'
minion2:
    ----------
    id:
        minion2
minion4:
    ----------
    id:
        minion4

Doing the same thing when executing the orchestrator returns an empty list:

# salt-run state.orchestrate orch.test1
master:
----------
          ID: Test db ['db', 'tcp', 1521]
    Function: cmd.run
        Name: echo "targets=[]"
      Result: True
     Comment: Command "echo "targets=[]"" run
     Started: 15:24:35.409293
    Duration: 6.648 ms
     Changes:   
              ----------
              pid:
                  44590
              retcode:
                  0
              stderr:
              stdout:
                  targets=[]
----------
          ID: Test back ['front', 'tcp', 80]
    Function: cmd.run
        Name: echo "targets=[]"
      Result: True
     Comment: Command "echo "targets=[]"" run
     Started: 15:24:35.416172
    Duration: 5.844 ms
     Changes:   
              ----------
              pid:
                  44591
              retcode:
                  0
              stderr:
              stdout:
                  targets=[]
----------
          ID: Test back ['db', 'tcp', 1521]
    Function: cmd.run
        Name: echo "targets=[]"
      Result: True
     Comment: Command "echo "targets=[]"" run
     Started: 15:24:35.422251
    Duration: 5.815 ms
     Changes:   
              ----------
              pid:
                  44592
              retcode:
                  0
              stderr:
              stdout:
                  targets=[]
----------
          ID: Test front ['back', 'tcp', 22]
    Function: cmd.run
        Name: echo "targets=[]"
      Result: True
     Comment: Command "echo "targets=[]"" run
     Started: 15:24:35.428300
    Duration: 5.847 ms
     Changes:   
              ----------
              pid:
                  44593
              retcode:
                  0
              stderr:
              stdout:
                  targets=[]
----------
          ID: Test front ['db', 'tcp', 1521]
    Function: cmd.run
        Name: echo "targets=[]"
      Result: True
     Comment: Command "echo "targets=[]"" run
     Started: 15:24:35.434381
    Duration: 6.042 ms
     Changes:   
              ----------
              pid:
                  44594
              retcode:
                  0
              stderr:
              stdout:
                  targets=[]

Summary for master
------------
Succeeded: 5 (changed=5)
Failed:    0
------------
Total states run:     5
Total run time:  30.196 ms

Expected behavior
Orchestrator result should be:

# salt-run state.orchestrate orch.test1
master:
----------
          ID: Test db ['db', 'tcp', 1521]
    Function: cmd.run
        Name: echo "targets=[ minion1 ]"
      Result: True
     Comment: Command "echo "targets=[ minion1 ]"" run
     Started: 15:24:35.409293
    Duration: 6.648 ms
     Changes:   
              ----------
              pid:
                  44590
              retcode:
                  0
              stderr:
              stdout:
                  targets=[ minion1 ]
----------
          ID: Test back ['front', 'tcp', 80]
    Function: cmd.run
        Name: echo "targets=[ minion3 ]"
      Result: True
     Comment: Command "echo "targets=[ minion3 ]"" run
     Started: 15:24:35.416172
    Duration: 5.844 ms
     Changes:   
              ----------
              pid:
                  44591
              retcode:
                  0
              stderr:
              stdout:
                  targets=[ minion3 ]
----------
          ID: Test back ['db', 'tcp', 1521]
    Function: cmd.run
        Name: echo "targets=[ minion1 ]"
      Result: True
     Comment: Command "echo "targets=[ minion1 ]"" run
     Started: 15:24:35.422251
    Duration: 5.815 ms
     Changes:   
              ----------
              pid:
                  44592
              retcode:
                  0
              stderr:
              stdout:
                  targets=[ minion1 ]
----------
          ID: Test front ['back', 'tcp', 22]
    Function: cmd.run
        Name: echo "targets=[ minion2,  minion4 ]"
      Result: True
     Comment: Command "echo "targets=[ minion2,  minion4 ]"" run
     Started: 15:24:35.428300
    Duration: 5.847 ms
     Changes:   
              ----------
              pid:
                  44593
              retcode:
                  0
              stderr:
              stdout:
                  targets=[ minion2,  minion4 ]
----------
          ID: Test front ['db', 'tcp', 1521]
    Function: cmd.run
        Name: echo "targets=[ minion1 ]"
      Result: True
     Comment: Command "echo "targets=[ minion1 ]"" run
     Started: 15:24:35.434381
    Duration: 6.042 ms
     Changes:   
              ----------
              pid:
                  44594
              retcode:
                  0
              stderr:
              stdout:
                  targets=[ minion1 ]

Summary for master
------------
Succeeded: 5 (changed=5)
Failed:    0
------------
Total states run:     5
Total run time:  30.196 ms

Versions Report

Salt Version:
          Salt: 3002.2
 
Dependency Versions:
          cffi: Not Installed
      cherrypy: unknown
      dateutil: 2.7.3
     docker-py: Not Installed
         gitdb: 2.0.6
     gitpython: 3.0.7
        Jinja2: 2.10.1
       libgit2: Not Installed
      M2Crypto: Not Installed
          Mako: 1.1.0
       msgpack: 0.6.2
  msgpack-pure: Not Installed
  mysql-python: Not Installed
     pycparser: Not Installed
      pycrypto: 2.6.1
  pycryptodome: 3.6.1
        pygit2: Not Installed
        Python: 3.8.5 (default, Jul 28 2020, 12:59:40)
  python-gnupg: 0.4.5
        PyYAML: 5.3.1
         PyZMQ: 18.1.1
         smmap: 2.0.5
       timelib: Not Installed
       Tornado: 4.5.3
           ZMQ: 4.3.2
 
System Versions:
          dist: ubuntu 20.04 focal
        locale: utf-8
       machine: x86_64
       release: 5.4.0-58-generic
        system: Linux
       version: Ubuntu 20.04 focal

Additional context
Add any other context about the problem here.

Reproduce the discrepancy with salt-run cache.mine, mine.get, and state.orchestrate orch.test1, comparing command-line and orchestration results. Trace how salt['mine.get'] resolves pillar targeting inside the orchestration SLS. Done means the orchestrator returns the same role-targeted minions as the command-line runner, with coverage for the reported setup.