Chain of a Chain with .apply() - fails to pass the right arguments

[AbdealiLoKo]

Checklist

• I have verified that the issue exists against the master branch of Celery.
• This has already been asked to the discussion group first.
• I have read the relevant section in the
  contribution guide
  on reporting bugs.
• I have checked the issues list
  for similar or identical bug reports.
• I have checked the pull requests list
  for existing proposed fixes.
• I have checked the commit log
  to find out if the bug was already fixed in the master branch.
• I have included all related issues and possible duplicate issues
  in this issue (If there are none, check this box anyway).

Mandatory Debugging Information

• I have included the output of celery -A proj report in the issue.
  (if you are not able to do this, then at least specify the Celery
  version affected).
• I have verified that the issue exists against the master branch of Celery.
• I have included the contents of pip freeze in the issue.
• I have included all the versions of all the external dependencies required
  to reproduce this bug.

Optional Debugging Information

• I have tried reproducing the issue on more than one Python version
  and/or implementation.
• I have tried reproducing the issue on more than one message broker and/or
  result backend.
• I have tried reproducing the issue on more than one version of the message
  broker and/or result backend.
• I have tried reproducing the issue on more than one operating system.
• I have tried reproducing the issue on more than one workers pool.
• I have tried reproducing the issue with autoscaling, retries,
  ETA/Countdown & rate limits disabled.
• I have tried reproducing the issue after downgrading
  and/or upgrading Celery and its dependencies.

Related Issues and Possible Duplicates

Related Issues

• None

Possible Duplicates

• None

Environment & Settings

Celery version:

celery report Output: /summary>

software -> celery:4.4.6 (cliffs) kombu:4.6.11 py:3.7.7
            billiard:3.6.3.0 py-amqp:2.6.0
platform -> system:Linux arch:64bit
            kernel version:4.4.0-18362-Microsoft imp:CPython
loader   -> celery.loaders.default.Loader
settings -> transport:amqp results:disabled

Steps to Reproduce

Required Dependencies

• Minimal Python Version: 3.7.7
• Minimal Celery Version: 4.4.2 / 4.4.6 / master
• Minimal Kombu Version: 4.6.11
• Minimal Broker Version: Using redis==3.5.3
• Minimal Result Backend Version: Using redis==3.5.3
• Minimal OS and/or Kernel Version: Linux Ubuntu 18.04
• Minimal Broker Client Version: Redis server v=4.0.9 sha=00000000:0 malloc=jemalloc-3.6.0 bits=64 build=9435c3c2879311f
• Minimal Result Backend Client Version: Redis server v=4.0.9 sha=00000000:0 malloc=jemalloc-3.6.0 bits=64 build=9435c3c2879311f

Python Packages

pip freeze Output:

amqp==2.6.0
appdirs==1.4.4
attrs==19.3.0
aws-xray-sdk==0.95
azure-common==1.1.5
azure-nspkg==3.0.2
azure-storage==0.36.0
azure-storage-common==1.1.0
azure-storage-nspkg==3.1.0
billiard==3.6.3.0
boto==2.49.0
boto3==1.14.13
botocore==1.17.13
case==1.5.3
-e git+git@github.com:celery/celery.git@f63a745e92c5b68385100a792a9d7ee23faf9dc8#egg=celery
certifi==2020.6.20
cffi==1.14.0
cfgv==3.1.0
chardet==3.0.4
cryptography==2.9.2
distlib==0.3.1
docker==4.2.1
docutils==0.15.2
ecdsa==0.15
filelock==3.0.12
future==0.18.2
identify==1.4.20
idna==2.10
importlib-metadata==1.7.0
Jinja2==2.11.2
jmespath==0.10.0
jsondiff==1.1.1
jsonpickle==1.4.1
kombu==4.6.11
linecache2==1.0.0
MarkupSafe==1.1.1
mock==4.0.2
more-itertools==8.4.0
moto==1.3.7
msgpack==1.0.0
nodeenv==1.4.0
nose==1.3.7
packaging==20.4
pluggy==0.13.1
pre-commit==2.5.1
py==1.9.0
pyaml==20.4.0
pycparser==2.20
pycryptodome==3.9.8
pylibmc==1.6.1
pyparsing==2.4.7
pytest==5.3.4
pytest-rerunfailures==9.0
python-dateutil==2.8.1
python-jose==2.0.2
pytz==2020.1
PyYAML==5.3.1
redis==3.5.3
requests==2.24.0
responses==0.10.15
s3transfer==0.3.3
simplejson==3.17.0
six==1.15.0
toml==0.10.1
traceback2==1.4.0
unittest2==1.1.0
urllib3==1.25.9
vine==1.3.0
virtualenv==20.0.25
wcwidth==0.2.5
websocket-client==0.57.0
Werkzeug==1.0.1
wrapt==1.12.1
xmltodict==0.12.0
zipp==3.1.0

Other Dependencies

N/A

Minimally Reproducible Test Case

c1 = chain(  # NOTE: This chain should have only 1 chain inside it
    chain(
        identity.s(),
        identity.s(),
    ),
)
res1 = c1.apply(args=(1,))
assert res1.get(timeout=TIMEOUT) == 1

Expected Behavior

This canvas should have been run and return 1 (as written in the assert)

Actual Behavior

When I run this with .apply(), it raises:

 TypeError: identity() missing 1 required positional argument: 'x'

When I run this with .apply_async(), using Redis as a broker+backend - it works.