diff --git a/.github/workflows/test_fast.yml b/.github/workflows/test_fast.yml
index 821760f9e5b..f779924ef90 100644
--- a/.github/workflows/test_fast.yml
+++ b/.github/workflows/test_fast.yml
@@ -20,11 +20,17 @@ jobs:
       fail-fast: false # Don't let a failed MacOS run stop the Ubuntu runs
       matrix:
         os: ['ubuntu-latest']
-        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
+        python-version: ['3.7', '3.8', '3.10', '3.11']
         include:
+          # mac os test
           - os: 'macos-latest'
-            python-version: '3.7'
+            python-version: '3.7'  # oldest supported version
+          # non-utc timezone test
+          - os: 'ubuntu-latest'
+            python-version: '3.9'  # not the oldest, not the most recent version
+            time-zone: 'XXX-09:35'
     env:
+      TZ: ${{ matrix.time-zone }}
       PYTEST_ADDOPTS: --cov --cov-append -n 5 --color=yes
     steps:
       - name: Checkout
diff --git a/cylc/flow/cycling/iso8601.py b/cylc/flow/cycling/iso8601.py
index 3c8bd3955fa..655c06c2881 100644
--- a/cylc/flow/cycling/iso8601.py
+++ b/cylc/flow/cycling/iso8601.py
@@ -943,12 +943,22 @@ def _interval_parse(interval_string):
 
 def point_parse(point_string: str) -> 'TimePoint':
     """Parse a point_string into a proper TimePoint object."""
-    return _point_parse(point_string, WorkflowSpecifics.DUMP_FORMAT)
+    return _point_parse(
+        point_string,
+        WorkflowSpecifics.DUMP_FORMAT,
+        WorkflowSpecifics.ASSUMED_TIME_ZONE
+    )
 
 
 @lru_cache(10000)
-def _point_parse(point_string, _dump_fmt):
-    """Parse a point_string into a proper TimePoint object."""
+def _point_parse(point_string: str, _dump_fmt, _tz) -> 'TimePoint':
+    """Parse a point_string into a proper TimePoint object.
+
+    Args:
+        point_string: The string to parse.
+        _dump_fmt: Dump format (only used to avoid invalid cache hits).
+        _tz: Cycle point time zone (only used to avoid invalid cache hits).
+    """
     if "%" in WorkflowSpecifics.DUMP_FORMAT:
         # May be a custom not-quite ISO 8601 dump format.
         with contextlib.suppress(IsodatetimeError):
diff --git a/pytest.ini b/pytest.ini
index 79cc3b55f54..9be86cb507c 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -32,9 +32,6 @@ testpaths =
     cylc/flow/
     tests/unit/
     tests/integration/
-env =
-    # a weird timezone to check that tests aren't assuming the local timezone
-    # TZ=XXX-09:35
 doctest_optionflags =
     NORMALIZE_WHITESPACE
     IGNORE_EXCEPTION_DETAIL
diff --git a/setup.cfg b/setup.cfg
index 25479541eaf..67ed7ac71c3 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -119,7 +119,6 @@ tests =
     pytest-asyncio>=0.17,!=0.23.*
     pytest-cov>=2.8.0
     pytest-xdist>=2
-    pytest-env>=0.6.2
     pytest>=6
     testfixtures>=6.11.0
     towncrier>=23
diff --git a/tests/integration/test_task_pool.py b/tests/integration/test_task_pool.py
index 2d13cd3d5c8..c334db83423 100644
--- a/tests/integration/test_task_pool.py
+++ b/tests/integration/test_task_pool.py
@@ -1291,7 +1291,6 @@ async def test_compute_runahead(
             'scheduler': {
                 'allow implicit tasks': 'True',
                 'cycle point format': 'CCYY',
-                'cycle point time zone': 'Z'
             },
             'scheduling': {
                 'initial cycle point': '0001',