Regression: Fix undefined presence after reconnect (#16477)

client/lib/userData.js

@@ -9,7 +9,8 @@ export const isSyncReady = new ReactiveVar(false);
 
 function updateUser(userData) {
 	const user = Users.findOne({ _id: userData._id });
-	if (!user || userData._updatedAt > user._updatedAt) {
+	if (!user || userData._updatedAt > user._updatedAt.toISOString()) {
+		userData._updatedAt = new Date(userData._updatedAt);
 		return Meteor.users.upsert({ _id: userData._id }, userData);
 	}
 	// delete data already on user's collection as those are newer

client/startup/startup.js

@@ -37,6 +37,9 @@ Meteor.startup(function() {
 		if (!uid) {
 			return;
 		}
+		if (!Meteor.status().connected) {
+			return;
+		}
 
 		const user = await syncUserdata(uid);
 		if (!user) {