diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/background_processing/celery_tasks/process_instance_task.py b/spiffworkflow-backend/src/spiffworkflow_backend/background_processing/celery_tasks/process_instance_task.py
index cd6b8476b..047d93cdc 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/background_processing/celery_tasks/process_instance_task.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/background_processing/celery_tasks/process_instance_task.py
@@ -1,7 +1,11 @@
+from typing import Any
 from billiard import current_process  # type: ignore
 from celery import shared_task
 from flask import current_app
 
+from spiffworkflow_backend.background_processing.celery_tasks.process_instance_task_producer import (
+    queue_future_task_if_appropriate,
+)
 from spiffworkflow_backend.background_processing.celery_tasks.process_instance_task_producer import (
     queue_process_instance_if_appropriate,
 )
@@ -23,9 +27,15 @@ class SpiffCeleryWorkerError(Exception):
     pass
 
 
+def get_current_process_index() -> Any:
+    raise Exception("NOOO")
+    # return current_process().index
+    return 1
+
+
 @shared_task(ignore_result=False, time_limit=ten_minutes)
 def celery_task_process_instance_run(process_instance_id: int, task_guid: str | None = None) -> dict:
-    proc_index = current_process().index
+    proc_index = get_current_process_index()
     ProcessInstanceLockService.set_thread_local_locking_context("celery:worker", additional_processing_identifier=proc_index)
     process_instance = ProcessInstanceModel.query.filter_by(id=process_instance_id).first()
 
@@ -71,6 +81,8 @@ def celery_task_process_instance_run(process_instance_id: int, task_guid: str |
             f"Could not run process instance with worker: {current_app.config['PROCESS_UUID']} - {proc_index}. Error was:"
             f" {str(exception)}"
         )
+        # NOTE: consider exponential backoff
+        queue_future_task_if_appropriate(process_instance, eta_in_seconds=10, task_guid=task_guid)
         return {"ok": False, "process_instance_id": process_instance_id, "task_guid": task_guid, "exception": str(exception)}
     except Exception as exception:
         db.session.rollback()  # in case the above left the database with a bad transaction
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/background_processing/celery_tasks/process_instance_task_producer.py b/spiffworkflow-backend/src/spiffworkflow_backend/background_processing/celery_tasks/process_instance_task_producer.py
index a774179d9..6ffc1e3c9 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/background_processing/celery_tasks/process_instance_task_producer.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/background_processing/celery_tasks/process_instance_task_producer.py
@@ -35,7 +35,9 @@ def should_queue_process_instance(process_instance: ProcessInstanceModel, execut
     return False
 
 
-def queue_future_task_if_appropriate(process_instance: ProcessInstanceModel, eta_in_seconds: float, task_guid: str) -> bool:
+def queue_future_task_if_appropriate(
+    process_instance: ProcessInstanceModel, eta_in_seconds: float, task_guid: str | None = None
+) -> bool:
     if queue_enabled_for_process_model(process_instance):
         buffer = 1
         countdown = eta_in_seconds - time.time() + buffer
diff --git a/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_process_instance_task.py b/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_process_instance_task.py
new file mode 100644
index 000000000..992258fd1
--- /dev/null
+++ b/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_process_instance_task.py
@@ -0,0 +1,59 @@
+from unittest.mock import patch
+from pytest_mock.plugin import MockerFixture
+from flask.app import Flask
+from spiffworkflow_backend.background_processing.celery_tasks.process_instance_task import celery_task_process_instance_run
+
+# from spiffworkflow_backend.background_processing.celery_tasks.process_instance_task_producer import (
+#     queue_future_task_if_appropriate,
+# )
+from spiffworkflow_backend.models.db import db
+import time
+from tests.spiffworkflow_backend.helpers.test_data import load_test_spec
+from spiffworkflow_backend.models.process_instance import ProcessInstanceStatus
+from spiffworkflow_backend.models.process_instance_queue import ProcessInstanceQueueModel
+from tests.spiffworkflow_backend.helpers.base_test import BaseTest
+
+
+class TestProcessInstanceTask(BaseTest):
+    def test_queues_process_instance_if_locked(
+        self,
+        app: Flask,
+        mocker: MockerFixture,
+        with_db_and_bpmn_file_cleanup: None,
+    ) -> None:
+        with self.app_config_mock(app, "SPIFFWORKFLOW_BACKEND_CELERY_ENABLED", True):
+            # mocked_process = mocker.Mock()
+            # mocked_process.index = 12345  # Setting the pid attribute to a mock value
+            # mocker.patch("billiard.current_process", return_value=mocked_process)
+
+            process_model = load_test_spec(
+                process_model_id="test_group/model_with_lanes",
+                bpmn_file_name="lanes.bpmn",
+                process_model_source_directory="model_with_lanes",
+            )
+            process_instance = self.create_process_instance_from_process_model(process_model=process_model, status="waiting")
+            assert process_instance.status == ProcessInstanceStatus.waiting.value
+            queue_entry = ProcessInstanceQueueModel.query.filter_by(process_instance_id=process_instance.id).first()
+            assert queue_entry is not None
+            queue_entry.locked_by = "test:test_waiting"
+            queue_entry.locked_at_seconds = round(time.time())
+            db.session.add(queue_entry)
+            db.session.commit()
+            # mocker.patch(
+            #     "spiffworkflow_backend.background_processing.celery_tasks.process_instance_task_producer.queue_future_task_if_appropriate"
+            # )
+
+            with patch(
+                "spiffworkflow_backend.background_processing.celery_tasks.process_instance_task.get_current_process_index"
+            ) as mock_proc_index:
+                mock_proc_index.return_value = 1
+                # with patch(
+                #     "spiffworkflow_backend.background_processing.celery_tasks.process_instance_task_producer.queue_future_task_if_appropriate"
+                # ) as mock_queue:
+                with patch(
+                    "spiffworkflow_backend.background_processing.celery_tasks.process_instance_task_producer.queue_future_task_if_appropriate"
+                ) as mock_queue:
+                    mock_queue.return_value = 1
+                    # mock = mocker.patch("billiard.current_process()", return_value=0)
+                    celery_task_process_instance_run(process_instance_id=process_instance.id)
+                    assert mock_queue.call_count == 1