Xdist sends invalid URL to selenium?

Hello. Please help me to figure out issue launch in parallel selenium based test via pytest and xdsit.
I have two firefox instance at docker and launch 2 independent test this way:
pytest -k "crypto" -n2

My Pipfile:

pytest==5.1.2
pytest-bdd==3.2.1
pytest-xdist==1.31.0
pytest-base-url==1.4.1
pytest-selenium==1.17.0

gcloud==0.18.3
firebase==3.0.1
python_jwt==3.2.4
sseclient-py==1.7
py-postgresql==1.2.1
requests-toolbelt==0.9.1
arrow==0.15.4
kombu==4.6.7

My pytest.ini

[pytest]
bdd_features_base_dir = tests
base_url = https://projectname.com
sensitive_url = https://projectname.com
addopts = --driver Remote
          --port 4444
          --capability browserName firefox
          --html tests/logs/report.html
          --cucumberjson=tests/uploads/cucumber.json
          --cucumberjson-expanded
          -v
filterwarnings =
    ignore::DeprecationWarning
markers =
    smoke: fast result
    crypto: add calculations

Here is track trace:

result = call_fixture_func(fixturefunc, request, kwargs)
../../.pyenv/versions/3.6.8/envs/projectname/lib/python3.6/site-packages/_pytest/fixtures.py:778: in call_fixture_func
res = fixturefunc(**kwargs)
tests/functional/test_02_deposit_by_dash.py:20: in user_signed_in
page_main.open()
../../.pyenv/versions/3.6.8/envs/projectname/lib/python3.6/site-packages/pypom/page.py:130: in open
self.driver_adapter.open(self.seed_url)
../../.pyenv/versions/3.6.8/envs/projectname/lib/python3.6/site-packages/pypom/selenium_driver.py:48: in open
self.driver.get(url)
../../.pyenv/versions/3.6.8/envs/projectname/lib/python3.6/site-packages/selenium/webdriver/remote/webdriver.py:333: in get
self.execute(Command.GET, {'url': url})
../../.pyenv/versions/3.6.8/envs/projectname/lib/python3.6/site-packages/selenium/webdriver/remote/webdriver.py:321: in execute
self.error_handler.check_response(response)

self = <selenium.webdriver.remote.errorhandler.ErrorHandler object at 0x10faa6f98>
response = {'status': 400, 'value': '{"value":{"error":"invalid argument","message":"Malformed URL: / is not a valid URL.","stack...dArgumentError@chrome://marionette/content/error.js:304:5\nget@chrome://marionette/content/listener.js:1132:19\n"}}'}
E selenium.common.exceptions.InvalidArgumentException: Message: Malformed URL: / is not a valid URL.

See more at screenshoot.
It works without -n2:
pytest -k "crypto"

Start with the reported pytest.ini settings and the pytest -k "crypto" -n2 command, then inspect tests/functional/test_02_deposit_by_dash.py where page_main.open() triggers the failure. Compare the URL passed to Selenium in parallel and non-parallel runs; done means parallel execution no longer sends '/' as the browser URL.