Steps to Reproduce

1. Create two test projects;
2. Give Assignable permission in the Project 1 to a single user.
3. In the Project 2, remove the assignable permission from the specific user.
4. Move the issue between the projects.
5. The user will continue assigned to the issue, even though the user does not have assignable permission in the Project 2

Expected Results

The issue should be reassigned according to the Default Assignee configurations of the target project.

Actual Results

The issue will continue assigned to the original user in the Project 1 even if the user has no permission to be the assignee.

Workaround:

Reassign the issue after moving it to the target project