Some fixes from backport (#89746)

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

x-pack/plugins/stack_alerts/common/build_sorted_events_query.ts

@@ -87,7 +87,7 @@ export const buildSortedEventsQuery = ({
         ...searchQuery.body,
         search_after: [searchAfterSortId],
       },
-    };
+    } as ESSearchRequest;
   }
-  return searchQuery;
+  return searchQuery as ESSearchRequest;
 };

x-pack/plugins/stack_alerts/server/alert_types/es_query/alert_type.ts

@@ -175,7 +175,17 @@ export function getAlertType(
               {
                 bool: {
                   must_not: [
-                    { bool: { filter: [{ range: { [params.timeField]: { lte: timestamp } } }] } },
+                    {
+                      bool: {
+                        filter: [
+                          {
+                            range: {
+                              [params.timeField]: { lte: new Date(timestamp).toISOString() },
+                            },
+                          },
+                        ],
+                      },
+                    },
                   ],
                 },
               },