Apple Music appears to be affected by a bug that is causing the app to install itself directly into the dock when downloaded from the App Store, with the app even replacing other first and third-party apps located in the dock.
There have been several complaints about the problem on Twitter from users who downloaded Apple Music and then had it replace another app. Kevin Archer, for example, had Apple Music replace Spotify in his dock.
Archer claimed that the app was only replacing non-Apple apps, but that appears to be incorrect, as TechCrunch tested the bug and had Apple Music install itself over the Camera app, Twitter, and Safari. We had it install over the Mail app and Dropbox, so music apps are not being targeted or solely impacted.
Seems like if you download the Apple Music app from App Store, it will automatically appear on your device (iPhone) dock, more than this, it will change any other 3d party app with the Music app. If on your dock, you only have Apple apps it won't do anything. pic.twitter.com/c0pkO9G2pq — Kevin Archer (@IM_Kevin_Archer) May 5, 2022
There have also been complaints that Apple Music is setting itself as the default music service when it is downloaded even if another music app was set as the default, but we have not been able to replicate this behavior.
iOS devices running iOS 15.4.1 are affected, and we were also able to get Apple Music to install itself over another app in the iOS 15.5 beta. Other older versions of iOS 15 also appear to be exhibiting the same issue. There's even a complaint from 2019, well before iOS 15.
As TechCrunch points out, this behavior has not explicitly been explained as a bug by Apple, but it is likely unintended. Apple has already been accused of favoring its own apps over third-party apps and is facing regulatory scrutiny, so there's little chance that Apple would blatantly replace third-party apps with its own.
There also appears to be no set pattern to the apps that Apple Music will replace, with Apple's own apps replaced as well, nor does the issue happen consistently. Epic CEO Tim Sweeney has, however, suggested that Apple "rigged" iOS to replace apps with Apple Music.
I just verified this on iOS 15.4.1. With Spotify installed and on the dock, installing Apple Music removed Spotify from the dock and put Apple Music there - without asking. Happens without Apple Music being run, so clearly Apple has rigged their OPERATING SYSTEM to do this! — Tim Sweeney (@TimSweeneyEpic) May 5, 2022
Given that the Apple Music issue is receiving quite a lot of attention, including accusations of preferential treatment, Apple will likely address it soon.
Update: Apple told MacRumors that it is aware of the issue and is looking into it.