diff --git a/src/slack/monitor/events/system-event-context.ts b/src/slack/monitor/events/system-event-context.ts
index 5df48dfd167..0c89ec2ce47 100644
--- a/src/slack/monitor/events/system-event-context.ts
+++ b/src/slack/monitor/events/system-event-context.ts
@@ -36,6 +36,7 @@ export async function authorizeAndResolveSlackSystemEventContext(params: {
   const sessionKey = ctx.resolveSlackSystemEventSessionKey({
     channelId,
     channelType: auth.channelType,
+    senderId,
   });
   return {
     channelLabel,