diff --git a/src/spyglass/utils/mixins/base.py b/src/spyglass/utils/mixins/base.py
index b9c7ed2d2..e10791dfb 100644
--- a/src/spyglass/utils/mixins/base.py
+++ b/src/spyglass/utils/mixins/base.py
@@ -36,24 +36,19 @@ def _graph_deps(self) -> list:
 
         return [TableChain, RestrGraph]
 
-    @property
+    @cached_property
     def _test_mode(self) -> bool:
         """Return True if in test mode.
 
         Avoids circular import. Prevents prompt on delete.
 
-        Note: Using @property instead of @cached_property so we always get
-        current value from dj.config, even if test_mode changes after first access.
-
         Used by ...
         - BaseMixin._spyglass_version
         - HelpersMixin
         """
-        import datajoint as dj
+        from spyglass.settings import test_mode
 
-        # Check dj.config directly instead of importing module-level variable
-        # which gets stale if load_config() is called after initial import
-        return dj.config.get("custom", {}).get("test_mode", False)
+        return test_mode
 
     @cached_property
     def _spyglass_version(self):
diff --git a/tests/utils/test_dj_helper_fn.py b/tests/utils/test_dj_helper_fn.py
index aa063648f..c688e04fd 100644
--- a/tests/utils/test_dj_helper_fn.py
+++ b/tests/utils/test_dj_helper_fn.py
@@ -9,3 +9,42 @@ def test_deprecation_factory(caplog, common):
     assert (
         "Deprecation:" in caplog.text
     ), "No deprecation warning logged on migrated table."
+
+
+def test_str_to_bool():
+    """Test str_to_bool function handles various string inputs correctly.
+    
+    This test verifies that str_to_bool properly converts string values
+    to booleans, which is essential for fixing issue #1528 where string
+    "false" was incorrectly evaluated as True.
+    """
+    from spyglass.utils.dj_helper_fn import str_to_bool
+    
+    # Test truthy strings (case insensitive)
+    assert str_to_bool("true") is True
+    assert str_to_bool("True") is True
+    assert str_to_bool("TRUE") is True
+    assert str_to_bool("t") is True
+    assert str_to_bool("T") is True
+    assert str_to_bool("yes") is True
+    assert str_to_bool("YES") is True
+    assert str_to_bool("y") is True
+    assert str_to_bool("Y") is True
+    assert str_to_bool("1") is True
+    
+    # Test falsy strings
+    assert str_to_bool("false") is False
+    assert str_to_bool("False") is False
+    assert str_to_bool("FALSE") is False
+    assert str_to_bool("no") is False
+    assert str_to_bool("n") is False
+    assert str_to_bool("0") is False
+    assert str_to_bool("") is False
+    assert str_to_bool("random_string") is False
+    
+    # Test non-string inputs
+    assert str_to_bool(True) is True
+    assert str_to_bool(False) is False
+    assert str_to_bool(None) is False
+    assert str_to_bool(0) is False
+    assert str_to_bool(1) is True
diff --git a/tests/utils/test_mixin.py b/tests/utils/test_mixin.py
index 9197c67b7..afde038c7 100644
--- a/tests/utils/test_mixin.py
+++ b/tests/utils/test_mixin.py
@@ -173,3 +173,25 @@ def test_mixin_del_orphans(dj_conn, Mixin, MixinChild):
     Mixin().delete_orphans(dry_run=False, safemode=False)
     post_del = Mixin().fetch1("id")
     assert post_del == 0, "Delete orphans not working."
+
+
+def test_test_mode_property_uses_settings(schema_test, Mixin):
+    """Test that _test_mode property uses spyglass.settings.config.
+    
+    Verifies fix for issue #1528 where string "false" was incorrectly 
+    evaluated as True. The property should now use spyglass.settings.config.test_mode
+    which properly converts strings to booleans via str_to_bool().
+    """
+    schema_test(Mixin)
+    
+    # The _test_mode property should return a boolean
+    test_mode_value = Mixin()._test_mode
+    assert isinstance(test_mode_value, bool), (
+        "_test_mode should return a boolean value"
+    )
+    
+    # In test environment, test_mode should be True
+    # (set by load_config fixture in conftest.py)
+    assert test_mode_value is True, (
+        "_test_mode should be True in test environment"
+    )