Pipeline job fails after tests complete

Question

There is job script:

image: python:3.7.9

stages:
    - test

run_ui_tests:
    tags:
        - est
    stage: test
    before_script:
        - echo "Prepairing enviroment..."
        - python --version
        - pip install -r requirements.txt
    script:
        - echo "Executing ui tests with Pytest..."
        - cd cio_tests
        - pytest -v authorize_test.py
    after_script:
        - echo "Cleaning test catalogue..."

job fails after all tests are completed:

What is the reason for this behaviour? After all, the tests are completed and one of the tests found a bug