diff --git a/src/uwtools/drivers/driver.py b/src/uwtools/drivers/driver.py
index 681d05683..2c448e496 100644
--- a/src/uwtools/drivers/driver.py
+++ b/src/uwtools/drivers/driver.py
@@ -54,14 +54,13 @@ def __init__(
             }
         )
         self._config_full: dict = config_input.data
-        config_intermediate, _ = walk_key_path(self._config_full, key_path or [])
-        self._platform = config_intermediate.get("platform")
+        self._config_intermediate, _ = walk_key_path(self._config_full, key_path or [])
         try:
-            self._config: dict = config_intermediate[self.driver_name]
+            self._config: dict = self._config_intermediate[self.driver_name]
         except KeyError as e:
             raise UWConfigError("Required '%s' block missing in config" % self.driver_name) from e
         if controller:
-            self._config[STR.rundir] = config_intermediate[controller][STR.rundir]
+            self._config[STR.rundir] = self._config_intermediate[controller][STR.rundir]
         self._validate(schema_file)
         dryrun(enable=dry_run)
 
@@ -200,10 +199,10 @@ def _validate(self, schema_file: Optional[Path] = None) -> None:
         :raises: UWConfigError if config fails validation.
         """
         if schema_file:
-            validate_external(schema_file=schema_file, config=self.config_full)
+            validate_external(schema_file=schema_file, config=self._config_intermediate)
         else:
             validate_internal(
-                schema_name=self.driver_name.replace("_", "-"), config=self.config_full
+                schema_name=self.driver_name.replace("_", "-"), config=self._config_intermediate
             )
 
 
@@ -390,13 +389,13 @@ def _run_resources(self) -> dict[str, Any]:
         """
         Returns platform configuration data.
         """
-        if not self._platform:
+        if not (platform := self._config_intermediate.get("platform")):
             raise UWConfigError("Required 'platform' block missing in config")
         threads = self.config.get(STR.execution, {}).get(STR.threads)
         return {
-            STR.account: self._platform[STR.account],
+            STR.account: platform[STR.account],
             STR.rundir: self.rundir,
-            STR.scheduler: self._platform[STR.scheduler],
+            STR.scheduler: platform[STR.scheduler],
             STR.stdout: "%s.out" % self._runscript_path.name,  # config may override
             **({STR.threads: threads} if threads else {}),
             **self.config.get(STR.execution, {}).get(STR.batchargs, {}),
@@ -481,10 +480,10 @@ def _validate(self, schema_file: Optional[Path] = None) -> None:
         :raises: UWConfigError if config fails validation.
         """
         if schema_file:
-            validate_external(schema_file=schema_file, config=self.config_full)
+            validate_external(schema_file=schema_file, config=self._config_intermediate)
         else:
             validate_internal(
-                schema_name=self.driver_name.replace("_", "-"), config=self.config_full
+                schema_name=self.driver_name.replace("_", "-"), config=self._config_intermediate
             )
         validate_internal(schema_name=STR.platform, config=self.config_full)
 
diff --git a/src/uwtools/tests/drivers/test_driver.py b/src/uwtools/tests/drivers/test_driver.py
index b52b3d4de..4b1a74f91 100644
--- a/src/uwtools/tests/drivers/test_driver.py
+++ b/src/uwtools/tests/drivers/test_driver.py
@@ -219,7 +219,6 @@ def test_Assets_key_path(config, tmp_path):
         config=config_file, dry_run=False, key_path=["foo", "bar"]
     )
     assert assetsobj.config == config[assetsobj.driver_name]
-    assert assetsobj._platform == config["platform"]
 
 
 def test_Assets_leadtime(config):
@@ -236,6 +235,14 @@ def test_Assets_validate(assetsobj, caplog):
     assert regex_logged(caplog, "State: Ready")
 
 
+def test_Assets_validate_key_path(config, controller_schema):
+    config = {"a": {"b": config}}
+    with patch.object(ConcreteAssetsTimeInvariant, "_validate", driver.Assets._validate):
+        assert ConcreteAssetsTimeInvariant(
+            config=config, key_path=["a", "b"], schema_file=controller_schema
+        )
+
+
 @mark.parametrize(
     "base_file,update_values,expected",
     [
@@ -442,7 +449,7 @@ def test_Driver__namelist_schema_default_disable(driverobj):
 
 
 def test_Driver__run_resources_fail(driverobj):
-    driverobj._platform = None
+    del driverobj._config_intermediate["platform"]
     with raises(UWConfigError) as e:
         assert driverobj._run_resources
     assert str(e.value) == "Required 'platform' block missing in config"