diff --git a/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/rules/find_rules_status_route.ts b/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/rules/find_rules_status_route.ts
index c496c7b7ce59c..5687c5d4095db 100644
--- a/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/rules/find_rules_status_route.ts
+++ b/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/rules/find_rules_status_route.ts
@@ -59,6 +59,10 @@ export const createFindRulesStatusRoute = (getClients: GetScopedClients): Hapi.S
           searchFields: ['alertId'],
         });
         const accumulated = await acc;
+
+        // Array accessors can result in undefined but
+        // this is not represented in typescript for some reason,
+        // https://github.com/Microsoft/TypeScript/issues/11122
         const currentStatus = convertToSnakeCase<IRuleStatusAttributes>(
           lastFiveErrorsForId.saved_objects[0]?.attributes
         );
diff --git a/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/utils.test.ts b/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/utils.test.ts
index 3148083b4db26..a382c4a323671 100644
--- a/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/utils.test.ts
+++ b/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/utils.test.ts
@@ -6,6 +6,8 @@
 
 import Boom from 'boom';
 
+import { SavedObjectsFindResponse } from 'kibana/server';
+import { IRuleSavedAttributesSavedObjectAttributes, IRuleStatusAttributes } from '../rules/types';
 import {
   transformError,
   transformBulkError,
@@ -323,5 +325,19 @@ describe('utils', () => {
       const values = {};
       expect(convertToSnakeCase(values)).toEqual({});
     });
+    it('returns null when passed in undefined', () => {
+      // Array accessors can result in undefined but
+      // this is not represented in typescript for some reason,
+      // https://github.com/Microsoft/TypeScript/issues/11122
+      const values: SavedObjectsFindResponse<IRuleSavedAttributesSavedObjectAttributes> = {
+        page: 0,
+        per_page: 5,
+        total: 0,
+        saved_objects: [],
+      };
+      expect(
+        convertToSnakeCase<IRuleStatusAttributes>(values.saved_objects[0]?.attributes) // this is undefined, but it says it's not
+      ).toEqual(null);
+    });
   });
 });
diff --git a/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/utils.ts b/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/utils.ts
index aaa5db7966b2b..65c9141619cb9 100644
--- a/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/utils.ts
+++ b/x-pack/legacy/plugins/siem/server/lib/detection_engine/routes/utils.ts
@@ -222,8 +222,9 @@ export const getIndex = (getSpaceId: () => string, config: LegacyServices['confi
   return `${signalsIndex}-${spaceId}`;
 };
 
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-export const convertToSnakeCase = <T extends Record<string, any>>(obj: T): Partial<T> | null => {
+export const convertToSnakeCase = <T extends Record<string, unknown>>(
+  obj: T
+): Partial<T> | null => {
   if (!obj) {
     return null;
   }
diff --git a/x-pack/legacy/plugins/siem/server/lib/detection_engine/rules/read_rules.test.ts b/x-pack/legacy/plugins/siem/server/lib/detection_engine/rules/read_rules.test.ts
index aa1cce6f15238..862ea9d2dcbe5 100644
--- a/x-pack/legacy/plugins/siem/server/lib/detection_engine/rules/read_rules.test.ts
+++ b/x-pack/legacy/plugins/siem/server/lib/detection_engine/rules/read_rules.test.ts
@@ -39,9 +39,9 @@ describe('read_rules', () => {
     });
     test('should return null if saved object found by alerts client given id is not alert type', async () => {
       const alertsClient = alertsClientMock.create();
-      const { alertTypeId, ...rest } = getResult();
-      // @ts-ignore
-      alertsClient.get.mockImplementation(() => rest);
+      const result = getResult();
+      delete result.alertTypeId;
+      alertsClient.get.mockResolvedValue(result);
 
       const rule = await readRules({
         alertsClient,
@@ -109,8 +109,7 @@ describe('read_rules', () => {
     test('should return null if the output from alertsClient with ruleId set is empty', async () => {
       const alertsClient = alertsClientMock.create();
       alertsClient.get.mockResolvedValue(getResult());
-      // @ts-ignore
-      alertsClient.find.mockResolvedValue({ data: [] });
+      alertsClient.find.mockResolvedValue({ data: [], page: 0, perPage: 1, total: 0 });
 
       const rule = await readRules({
         alertsClient,