Items disappearing on drag-and-drop

### Which @angular/* package(s) are the source of the bug?

animations

### Is this a regression?

Yes

### Description

Our Angular web app allows users to drag-and-drop components to reorder them.

Recently, we noticed that dragging-and-dropping was causing items to disappear from the page entirely!

Please see the attached mp4 video for a demonstration of this behavior against a minimal repro (stackblitz link for this repro is included below)

---

We suspect it was caused by a change in the `animations` package, and we were able to mitigate the "disappearing" issue by removing these two lines from the relevant HTML snippet (i.e. disabling the animation):

```
animate.enter="ease-in-animation"
animate.leave="ease-out-animation"
```

I believe this behavior is new as of release `21.2.0-rc.0` - I've pinned all Angular packages to that version in the repro link below

### Please provide a link to a minimal reproduction of the bug

https://stackblitz.com/edit/stackblitz-starters-2puwya73?file=src%2Fapp.component.html

### Please provide the exception or error you saw

```true

```

### Please provide the environment you discovered this bug in (run `ng version`)

```true
$ ng version

     _                      _                 ____ _     ___
    / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
   / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
  / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
 /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                |___/
    

Angular CLI       : 21.2.0-rc.0
Angular           : 21.2.0-rc.0
Node.js           : 20.19.1
Package Manager   : npm 10.8.2
Operating System  : linux x64

┌───────────────────────────┬───────────────────┬───────────────────┐
│ Package                   │ Installed Version │ Requested Version │
├───────────────────────────┼───────────────────┼───────────────────┤
│ @angular/animations       │ 21.2.0-rc.0       │ 21.2.0-rc.0       │
│ @angular/build            │ 21.2.0-rc.0       │ 21.2.0-rc.0       │
│ @angular/cdk              │ 21.2.0-rc.0       │ 21.2.0-rc.0       │
│ @angular/cli              │ 21.2.0-rc.0       │ 21.2.0-rc.0       │
│ @angular/common           │ 21.2.0-rc.0       │ 21.2.0-rc.0       │
│ @angular/compiler         │ 21.2.0-rc.0       │ ^21.2.0-rc.0      │
│ @angular/compiler-cli     │ 21.2.0-rc.0       │ 21.2.0-rc.0       │
│ @angular/core             │ 21.2.0-rc.0       │ 21.2.0-rc.0       │
│ @angular/forms            │ 21.2.0-rc.0       │ 21.2.0-rc.0       │
│ @angular/platform-browser │ 21.2.0-rc.0       │ 21.2.0-rc.0       │
│ @angular/router           │ 21.2.0-rc.0       │ 21.2.0-rc.0       │
│ rxjs                      │ 7.8.2             │ ^7.8.1            │
│ typescript                │ 5.9.3             │ ^5.9.3            │
└───────────────────────────┴───────────────────┴───────────────────┘
```

### Anything else?

https://github.com/user-attachments/assets/dbf0702c-e61f-4cb3-8ee5-c2c80b2c8cc1

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Items disappearing on drag-and-drop #67257

Which @angular/* package(s) are the source of the bug?

Is this a regression?

Description

Please provide a link to a minimal reproduction of the bug

Please provide the exception or error you saw

Please provide the environment you discovered this bug in (run `ng version`)

Anything else?

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Items disappearing on drag-and-drop #67257

Description

Which @angular/* package(s) are the source of the bug?

Is this a regression?

Description

Please provide a link to a minimal reproduction of the bug

Please provide the exception or error you saw

Please provide the environment you discovered this bug in (run ng version)

Anything else?

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

Please provide the environment you discovered this bug in (run `ng version`)