pytest_fixture_setup hook doesn't run for session scoped fixture

test\conftest.py

import pytest

@pytest.fixture(scope='function')
# @pytest.fixture(scope='session')
def fixture_1():
    return None


@pytest.hookimpl(tryfirst=True)
def pytest_fixture_setup(fixturedef, request):
    print('Fixture setup: ', fixturedef.argname)

test/test_1.py

def test_1(fixture_1):
    assert 1

If we run pytest test we get

$ pytest test -s
============================= test session starts ==============================
platform linux -- Python 3.6.9, pytest-5.4.3, py-1.9.0, pluggy-0.13.1
rootdir: /home/voronin/projects/sintez_addons, inifile: setup.cfg
collected 1 item                                                               

test/test_1.py Fixture setup:  fixture_1
.

============================== 1 passed in 0.01s ==============================

If we change fixture_1 scope to session there is no hook running.

$ pytest test -s
============================= test session starts ==============================
platform linux -- Python 3.6.9, pytest-5.4.3, py-1.9.0, pluggy-0.13.1
rootdir: /home/voronin/projects/sintez_addons, inifile: setup.cfg
collected 1 item                                                               

test/test_1.py .

============================== 1 passed in 0.01s ===============================

IMHO problem in this code

hook = self._fixturemanager.session.gethookproxy(request.node.fspath)

In function scope case:

request.node.fspath == '/home/voronin/projects/sintez_addons'
hook is <_pytest.main.FSHookProxy object at 0x7f9200a69250>

In session scope case:

request.node.fspath == '/home/voronin/projects/sintez_addons/test/test_1.py'
hook is <pluggy.hooks._HookRelay object at 0x7f10c2952710>

Reproduce the behavior with test/conftest.py and test/test_1.py, comparing function- and session-scoped fixtures. Start at the fixture manager hook-proxy call shown in the report and trace how pytest_fixture_setup is selected for each scope. Done means the hook runs for the session-scoped fixture while the example test still passes.