diff --git a/src/lib/services/client-metrics/index.ts b/src/lib/services/client-metrics/index.ts
index 436f1e7008..874261eff4 100644
--- a/src/lib/services/client-metrics/index.ts
+++ b/src/lib/services/client-metrics/index.ts
@@ -22,7 +22,11 @@ import {
     IMetricsBucket,
 } from '../../types/model';
 import { clientRegisterSchema } from './register-schema';
-import { minutesToMilliseconds, secondsToMilliseconds } from 'date-fns';
+import {
+    minutesToMilliseconds,
+    parseISO,
+    secondsToMilliseconds,
+} from 'date-fns';
 import TTLList = require('./ttl-list');
 
 export default class ClientMetricsService {
@@ -352,8 +356,9 @@ export default class ClientMetricsService {
             count += countObj.yes + countObj.no;
         });
 
-        this.lastHourList.add(toggles, stop);
-        this.lastMinuteList.add(toggles, stop);
+        const timestamp = typeof stop === 'string' ? parseISO(stop) : stop;
+        this.lastHourList.add(toggles, timestamp);
+        this.lastMinuteList.add(toggles, timestamp);
 
         this.globalCount += count;
         // eslint-disable-next-line no-param-reassign