# Bug OP-9379 - Internal error when trying to set milestone as parent wp

Project: OpenProject
Status: closed
URL: https://community.openproject.org/work_packages/OP-9379

## Open points

_No work packages_

## Details

| Attribute | Value |
| --- | --- |
| Date |  |
| Priority | Medium |
| Module |  |
| Target versions | 12.1.0 |
| Observed in versions | 12.0.0 |
| Sprint | 12.1.0 |
| Backlog bucket |  |
| Bug found in version (deprecated) | 12.0.x |
| Found in mobile app version |  |
| Follow-up feedback e-mail |  |
| Requires doc change | No |
| Accessibility | No |
| Pull preview |  |
| List |  |
| Labels |  |

## People

| Attribute | Value |
| --- | --- |
| Assignee |  |
| Accountable |  |
| Product manager |  |
| Developers |  |
| Designer |  |
| Ordered by |  |
| Signed off by |  |
| Interest by |  |

## Planning

| Attribute | Value |
| --- | --- |
| Relevance |  |

## Costs

| Attribute | Value |
| --- | --- |
| Votes |  |
| Work |  |
| Labor costs |  |

## Description

### **Environment**:

qa-stage

### **Steps to reproduce:**

1.  Open work package.
2.  Change parent work package to milestone.

### **Actual Behavior**

<figure class="image op-uc-figure"><div class="op-uc-figure--content"><img class="op-uc-image" src="/api/v3/attachments/23111/content"></div></figure>

###