### Steps to reproduce

1. Begin of the insertionLogin as a user with permission to edit WP

2. Go to workpackages page

3. Select a Project

4. Click on plus button in header

5. Select a WP type

6. End of the insertion Add a workpackage

Begin of the insertion7.End of the insertion Begin of the deletion 2.End of the deletion Fill fields required

Begin of the insertion8.End of the insertion Begin of the deletion 3.End of the deletion Hit Save


Begin of the insertionImportant: If you repeat creating the WP in the same project, the bug won't happen, but if you change the project, it will be there again.

End of the insertion ### What is the buggy behavior?

* An error message appears: are you sure you want to cancel editing the workpackage?

* When hitting OK the message 'creating workpackage success' (fortunately).


### What is the expected behavior?

1. No error message, just the confirmation that te work package is created.


### Screenshots and other files

Yes

### Environment information

_Please check and fill out the following details to help us identify in what versions and distributions of OpenProject the error occurs_

**OpenProject installation type**

* Packaged installation

* Ubuntu


**OpenProject version**

_V15.11_

**Browser**

* [ ] Chrome
* [ ] Firefox
* [x] Safari
* [ ] Mobile Safari
* [ ] Other (please specify)

**Operating System**

* [ ] Windows
* [x] MacOS 15.2
* [ ] Mobile iOS
* [ ] Mobile Android
* [ ] Linux (please specify distro)
* [ ] Chrome OS
* [ ] Other (please specify)

**Language**

Browser and OP language: NL