MacworldApples latest mid-size iPhone software update, iOS 18.4, brings dozens of improvements. But as is often the case when an operating system changes in a significant way, it brings problems too. Including a newly reported and annoying-sounding bug that reinstalls users deleted apps.In a thread posted Tuesday on the Apple Community discussion site (via 9to5Mac), a user complains about an unwanted app reappearing inexplicably on their phone. There seems to be no possible cause for this other than the iOS 18.4 update.After upgrading to iOS 18.4, my iPhone randomly installed Last War: Survival, the user writes. (This looks to be one of those dubious free games heavily advertised online.) This app was previously installed on my iPhone a few months ago but uninstalled after a few hours. Now it appeared back on my Home Screen.Given that the author of the thread uses the alias Someandroiduser one might suspect the veracity of this account, despite their reassurances that the iPhone in question was never jailbroken, had never run any alternative app stores, and did not have automated app installs or syncs enabled. But for corroboration they post links to four separate Reddit threads in which other users complain of the same issue. I havent noticed the problem myself, but it would be folly to dismiss this as a false alarm.In fact, many of the Reddit posters hint at a worse problem than the already annoying issue of reinstalling deleted apps. Several, including a respondent to Someandroidusers Apple Community post (I had NBA 2k25 randomly download, and yet Im certain that Ive never installed the app previously), complain that apps they had never installed have been added to their devices. That has the potential to cause far more trouble, because you wouldnt have had the chance to vet such apps before they appeared. One would hope there wouldnt be many out-and-out scam apps on Apples store, but they do crop up from time to time. And simply having your childs iPhone install something with aggressive advertising or in-app purchases could lead to other problems down the line.To give an impression of the scale of the problem, Ive cherry-picked a few comments from across the threads:Same here. Different game though. I didnt recognize the game.Samenot one but three!When I updated, the game Infinite Lagrange was reinstalled even though I had uninstalled it.I left the phone updating then when I came back I had 5 apps randomly installed, and the phone was oddly hot.I know for a fact Ive never downloaded it before because I always hated the fake ads from that game.Never even heard of the game before, just appeared after updating to 18.4. Its not even in my list of downloaded apps.My phone automatically started installing Squid Game.My [iPhone] started installing PUBG Mbile when I remember that is the last app I searched before 18.4 installation I believe.Okay so after updating to iOS 18.4 successfully, I went to the App Store to update apps. And to my surprise this Chinese game installed itself automatically. How is it possible?I got Warzone lol. Installed itself automatically.This isnt the first bug to hit iOS 18.4, which had previously been implicated in users AirPods Max headphones not gaining lossless audio over USB-C. But this is a potentially far more serious lapse, mainly because it has the potential to affect far more people. (9to5Mac insists that were not seeing enough reports to indicate that its affecting more than a small minority of users, and I suppose that is technically truebut the 53 complaints I counted across those four Reddit threads and one Apple Community post suggest a major problem to me.) It could also do major damage to Apples image: those who see apps reappearing after being deleting will be annoyed; those who see entirely new apps popping up randomly are liable to lose their faith in Apples security.A fix needs to be rolled out, and soon. For this reason wed advise keeping an eye out for future updates and installing them in a timely fashion.