pytest is leaving behind symlink'd directories in tmpdir

My regression tests are leaving behind a symlink'd folder ending in "current" for every test executed. This ends up publishing duplicate folders as artifacts into my CI system. From what I have seen these folders should be cleaned up by pytest automatically, no?

I'm using the tmpdir_factory fixture in various session-level fixtures, and tmpdir in various tests to create files in the temp folder like so:

@pytest.fixture(scope='session')
def some_session_level_fixture(tmpdir_factory):
    some_file = os.path.join(tmpdir_factory.getbasetemp(), 'some_file')
    with open(some_file, 'w') as f:
          ...do stuff

And

def some_test(tmpdir):
    some_file = os.path.join(tmpdir, 'some_file')
    with open(some_file, 'w') as f:
          ...do stuff

It does this on both Python 3.5 and 3.7 on both Ubuntu Linux 16.04 and 19.04. I am running pytest via pipenv and My pipenv environment looks like this:

boto3==1.9.140
  - botocore [required: >=1.12.140,<1.13.0, installed: 1.12.140]
    - docutils [required: >=0.10, installed: 0.14]
    - jmespath [required: >=0.7.1,<1.0.0, installed: 0.9.4]
    - python-dateutil [required: >=2.1,<3.0.0, installed: 2.8.0]
      - six [required: >=1.5, installed: 1.12.0]
    - urllib3 [required: >=1.20,<1.25, installed: 1.24.3]
  - jmespath [required: >=0.7.1,<1.0.0, installed: 0.9.4]
  - s3transfer [required: >=0.2.0,<0.3.0, installed: 0.2.0]
    - botocore [required: >=1.12.36,<2.0.0, installed: 1.12.140]
      - docutils [required: >=0.10, installed: 0.14]
      - jmespath [required: >=0.7.1,<1.0.0, installed: 0.9.4]
      - python-dateutil [required: >=2.1,<3.0.0, installed: 2.8.0]
        - six [required: >=1.5, installed: 1.12.0]
      - urllib3 [required: >=1.20,<1.25, installed: 1.24.3]
matplotlib==3.0.3
  - cycler [required: >=0.10, installed: 0.10.0]
    - six [required: Any, installed: 1.12.0]
  - kiwisolver [required: >=1.0.1, installed: 1.1.0]
    - setuptools [required: Any, installed: 41.0.1]
  - numpy [required: >=1.10.0, installed: 1.16.3]
  - pyparsing [required: >=2.0.1,!=2.1.6,!=2.1.2,!=2.0.4, installed: 2.4.0]
  - python-dateutil [required: >=2.1, installed: 2.8.0]
    - six [required: >=1.5, installed: 1.12.0]
paho-mqtt==1.4.0
paramiko==2.4.2
  - bcrypt [required: >=3.1.3, installed: 3.1.6]
    - cffi [required: >=1.1, installed: 1.12.3]
      - pycparser [required: Any, installed: 2.19]
    - six [required: >=1.4.1, installed: 1.12.0]
  - cryptography [required: >=1.5, installed: 2.6.1]
    - asn1crypto [required: >=0.21.0, installed: 0.24.0]
    - cffi [required: >=1.8,!=1.11.3, installed: 1.12.3]
      - pycparser [required: Any, installed: 2.19]
    - six [required: >=1.4.1, installed: 1.12.0]
  - pyasn1 [required: >=0.1.7, installed: 0.4.5]
  - pynacl [required: >=1.0.1, installed: 1.3.0]
    - cffi [required: >=1.4.1, installed: 1.12.3]
      - pycparser [required: Any, installed: 2.19]
    - six [required: Any, installed: 1.12.0]
pytest==4.4.1
  - atomicwrites [required: >=1.0, installed: 1.3.0]
  - attrs [required: >=17.4.0, installed: 19.1.0]
  - more-itertools [required: >=4.0.0, installed: 7.0.0]
  - pluggy [required: >=0.9, installed: 0.9.0]
  - py [required: >=1.5.0, installed: 1.8.0]
  - setuptools [required: Any, installed: 41.0.1]
  - six [required: >=1.10.0, installed: 1.12.0]
requests==2.21.0
  - certifi [required: >=2017.4.17, installed: 2019.3.9]
  - chardet [required: >=3.0.2,<3.1.0, installed: 3.0.4]
  - idna [required: >=2.5,<2.9, installed: 2.8]
  - urllib3 [required: >=1.21.1,<1.25, installed: 1.24.3]
websockets==7.0

Start by reproducing the leftover symlinked directories with pytest's tmpdir_factory and tmpdir fixtures using the reported pytest 4.4.1 environment. Trace temporary-directory cleanup from those fixture entry points; done means session and test temporary data no longer leave the reported "current" symlinked directories behind.