Auto-created project key contains illegal characters

When creating a repository, a user is allowed to create a project using that same form. Using that functionality, the user only provides the project name (and not the key); the key is automatically generated from the name.

If the auto-generated key conflicts with another pre-existing key, then Bitbucket attempts to resolve the conflict by adding numbers at the end of the auto-generated key. Unfortunately, it uses a hyphen to separate the candidate key and the postfix number, which happens to be an illegal character. When a further attempt to modify any setting in that project is made, the attempt fails because an illegal key is in use.

Error message:

• Project keys must start with a letter and may only consist of ASCII letters, numbers and underscores (A-Z, a-z, 0-9, _)