diff --git a/lib/pact_broker/matrix/deployment_status_summary.rb b/lib/pact_broker/matrix/deployment_status_summary.rb
index 2b60c2aaa..3626932d6 100644
--- a/lib/pact_broker/matrix/deployment_status_summary.rb
+++ b/lib/pact_broker/matrix/deployment_status_summary.rb
@@ -1,3 +1,5 @@
+require 'pact_broker/logging'
+
 module PactBroker
   module Matrix
     class DeploymentStatusSummary
@@ -82,7 +84,13 @@ def missing_reasons
       end
 
       def resolved_version_for(pacticipant_id)
-        resolved_selectors.find{ | s| s[:pacticipant_id] == pacticipant_id }[:pacticipant_version_number]
+        resolved_selector = resolved_selectors.find{ | s| s[:pacticipant_id] == pacticipant_id }
+        if resolved_selector
+          resolved_selector[:pacticipant_version_number]
+        else
+          PactBroker.logger.warn "Could not find the resolved version for pacticipant_id #{pacticipant_id} from integrations #{integrations.collect(&:to_s).join(", ")} in resolved selectors #{resolved_selectors.inspect}"
+          "unresolved version"
+        end
       end
     end
   end
diff --git a/spec/lib/pact_broker/matrix/deployment_status_summary_spec.rb b/spec/lib/pact_broker/matrix/deployment_status_summary_spec.rb
index dea249987..e3409169b 100644
--- a/spec/lib/pact_broker/matrix/deployment_status_summary_spec.rb
+++ b/spec/lib/pact_broker/matrix/deployment_status_summary_spec.rb
@@ -7,7 +7,6 @@ module PactBroker
   module Matrix
     describe DeploymentStatusSummary do
       describe ".call" do
-
         let(:rows) { [row_1, row_2] }
         let(:row_1) do
           double(Row,
@@ -52,7 +51,6 @@ module Matrix
           ]
         end
 
-
         subject { DeploymentStatusSummary.new(rows, resolved_selectors, integrations) }
 
         context "when there is a row for all integrations" do
@@ -92,6 +90,26 @@ module Matrix
           its(:reasons) { is_expected.to eq ["There is no verified pact between Foo (ddec8101dabf4edf9125a69f9a161f0f294af43c) and Baz (4ee06460f10e8207ad904fa9fa6c4842e462ab59)"] }
           its(:counts) { is_expected.to eq success: 1, failed: 0, unknown: 1 }
         end
+
+        context "when there is something unexpected about the data and the resolved selector cannot be found" do
+          let(:rows) { [row_1] }
+
+          let(:resolved_selectors) do
+            [
+              {
+                pacticipant_id: 3, pacticipant_version_number: "4ee06460f10e8207ad904fa9fa6c4842e462ab59"
+              }
+            ]
+          end
+
+          its(:deployable?) { is_expected.to be nil }
+          its(:reasons) { is_expected.to eq ["There is no verified pact between Foo (unresolved version) and Baz (4ee06460f10e8207ad904fa9fa6c4842e462ab59)"] }
+
+          it "logs a warning" do
+            expect(PactBroker.logger).to receive(:warn).with(/Could not find the resolved version/)
+            subject.reasons
+          end
+        end
       end
     end
   end