[Bug]: LocalClient ignores returns in syndic-hierarchy

What happened?

When running an execution module via the LocalClient, minions returns below some syndics are completely ignored.

cmd_iter and cmd_batch stop after syndic0 returns
syndic1 and syndic2 are ignored despite return-events being sent to the eventbus
setting higher timeout-values does nothing
expect_minions:True does nothing either

cmd_async and get_cache_returns will show all returns as long as the wait time between the two commands is long enough

-> saltutil.cmd uses the LocalClient with cmd_iter per default or cmd_batch if batch is set and will also ignore returns

Type of salt install

Official deb

Major version

3006.x

What supported OS are you seeing the problem on? Can select multiple. (If bug appears on an unsupported OS, please open a GitHub Discussion instead)

ubuntu-24.04, ubuntu-22.04

salt --versions-report output

Master-of-Masters
Salt Version:
          Salt: 3006.27

Python Version:
        Python: 3.11.15 (main, Jun 29 2026, 22:21:49) [GCC 11.2.0]

Dependency Versions:
          cffi: 2.0.0
      cherrypy: 18.10.0
  cryptography: 47.0.0
      dateutil: 2.9.0.post0
     docker-py: Not Installed
         gitdb: 4.0.12
     gitpython: 3.1.50
        Jinja2: 3.1.6
       libgit2: Not Installed
  looseversion: 1.3.0
      M2Crypto: Not Installed
          Mako: Not Installed
       msgpack: 1.1.2
  msgpack-pure: Not Installed
  mysql-python: Not Installed
     packaging: 24.0
     pycparser: 3.00
      pycrypto: Not Installed
  pycryptodome: 3.23.0
        pygit2: Not Installed
  python-gnupg: 0.5.6
        PyYAML: 6.0.3
         PyZMQ: 27.1.0
        relenv: 0.22.16
         smmap: 5.0.2
       timelib: 0.3.0
       Tornado: 6.5.5
           ZMQ: 4.3.5

System Versions:
          dist: ubuntu 22.04.5 jammy
        locale: utf-8
       machine: x86_64
       release: 5.15.0-186-generic
        system: Linux
       version: Ubuntu 22.04.5 jammy


Syndics:
Salt Version:
          Salt: 3006.27

Python Version:
        Python: 3.11.15 (main, Jun 29 2026, 22:21:49) [GCC 11.2.0]

Dependency Versions:
          cffi: 2.0.0
      cherrypy: 18.10.0
  cryptography: 47.0.0
      dateutil: 2.9.0.post0
     docker-py: Not Installed
         gitdb: 4.0.12
     gitpython: 3.1.50
        Jinja2: 3.1.6
       libgit2: Not Installed
  looseversion: 1.3.0
      M2Crypto: Not Installed
          Mako: Not Installed
       msgpack: 1.1.2
  msgpack-pure: Not Installed
  mysql-python: Not Installed
     packaging: 24.0
     pycparser: 3.00
      pycrypto: Not Installed
  pycryptodome: 3.23.0
        pygit2: Not Installed
  python-gnupg: 0.5.6
        PyYAML: 6.0.3
         PyZMQ: 27.1.0
        relenv: 0.22.16
         smmap: 5.0.2
       timelib: 0.3.0
       Tornado: 6.5.5
           ZMQ: 4.3.5

System Versions:
          dist: ubuntu 24.04.4 noble
        locale: utf-8
       machine: x86_64
       release: 6.8.0-136-generic
        system: Linux
       version: Ubuntu 24.04.4 noble