Error when Updating Custom Text in New Universal Login Prompt "Key <...> in screen <...> has invalid characters"

When trying to update custom text in a new universal login prompt, the following error is returned, indicating that the key has invalid characters.

Example:

{
"statusCode": 400,
"error": "Bad Request",
"message": "Key \"usernameDescription\" in screen \"reset-password-email\" has invalid characters.",
"errorCode": "invalid_body"
}

• New Universal Login
• Custom Text

This error occurs if the key value contains any liquid directive tags {% %}, any mustache tags {{ }}, or any HTML tags <tag>.

Remove any of the following from the key's value:

• Liquid directive tags: {% %}
• Moustache tags {{ }}
• HTML tags: <tag>