Broken branch permissions on repository if Project branch permissions are set on project level

Summary

On Bitbucket 6.1.0 (and 6.1.1), if there are branch permissions set on project level, the branch permissions page on the repository level in the project becomes broken

How to Replicate

1. Create a new project.
2. Create a new repository in the project
3. Create a branch permission on the repository
4. Create a branch permission on the project
5. Open branch permissions configuration on the repository
   • Permissions are not shown, and it is not possible to add new permissions
6. Remove branch permission on project level
   • Open branch permissions configuration on the repository
7. Permissions are shown, and it is possible to add new permissions

Expected Results

It's possible to create branch permissions on repo level without problems

Actual Results

It's not possible to create branch permissions on repo level if there is already a project level branch permissions set.

On the console, the following error is shown:

Workaround

Set any branch permissions on the repo level first before setting them on the project level