diff --git a/lib/push/send-utils.js b/lib/push/send-utils.js
--- a/lib/push/send-utils.js
+++ b/lib/push/send-utils.js
@@ -51,6 +51,7 @@
 import { type GetENSNames } from '../utils/ens-helpers.js';
 import { type GetFCNames } from '../utils/farcaster-helpers.js';
 import { promiseAll } from '../utils/promises.js';
+import invariant from 'invariant';
 
 export type Device = {
   +platformDetails: PlatformDetails,
@@ -134,6 +135,11 @@
   for (const threadID of threadsToMessageIndices.keys()) {
     const threadInfo = rawThreadInfos[threadID];
     for (const memberInfo of threadInfo.members) {
+      // TODO: `getPushUserInfo` needs to be typed to only accept `ThickRawThreadInfo`.
+      invariant(
+        memberInfo && memberInfo.permissions,
+        'memberInfo must be set in getPushUserInfo',
+      );
       if (
         !isMemberActive(memberInfo) ||
         !hasPermission(memberInfo.permissions, 'visible') ||