Incorrect error message when creating new branch from Web IDE with restricted name

If a repository has configured restrictions for branch names under Settings → Repository → Push Rules → branch name, and someone, using the Web IDE chooses "Create a new branch" or "Create a new branch and merge request", and chooses a name that does not conform to the naming restrictions, then the error received will be "This branch has changed since you started editing. Would you like to create a new branch?".

This error message correctly identifies that there is a problem creating the branch, but the message does not accurately describe why it failed, or what should be done about it. Choosing the "Create new branch" button causes the error to go away and come back. Choosing "Cancel" will allow the user to make another selection for commiting the changes.