diff --git a/applications/abri/dispatch.py b/applications/abri/dispatch.py
index 092c0a59c..2362fa1d0 100644
--- a/applications/abri/dispatch.py
+++ b/applications/abri/dispatch.py
@@ -99,6 +99,10 @@ def dispatch_abri_flows(
 
 
 def _run_amend(request: AbriTriggerRequest, flows: AbriFlows) -> str:
+    if request.client_booking_reference is None:
+        raise DealDivergedFromAbriError(
+            flow="amend_job", deal_id=request.hubspot_deal_id
+        )
     if (
         request.confirmed_survey_date is None
         or request.third_party_surveyor_identifier is None
@@ -165,8 +169,13 @@ def _run_log(
 
 def _run_abandon(request: AbriTriggerRequest, flows: AbriFlows) -> str:
     # Runs last so a cancellation can never interfere with a log, amend or
-    # tenant sync in the same batch. A missing job_no raises the retriable
-    # not-yet-recorded error, which propagates so the task fails and redelivers.
+    # tenant sync in the same batch. With a Job Number, a missing DB job_no
+    # raises the retriable not-yet-recorded error, which propagates so the task
+    # fails and redelivers; with no Job Number at all, the deal has diverged.
+    if request.client_booking_reference is None:
+        raise DealDivergedFromAbriError(
+            flow="abandon_job", deal_id=request.hubspot_deal_id
+        )
     outcome = flows.abandon_job(
         DealAbandonment(
             deal_id=request.hubspot_deal_id,