Why does Laravel's validator->messages() start returning lower case errors?

Question

Laravel

Good time!
Has anyone encountered such a problem that the $validator->messages() method started returning an error in lower case? Or rather, the name of the fields in lowercase, so it is also merged if the field consists of several words.
For example: the field "Problem Description" error returns the following. way "The problem description field is mandatory" At the same time, the Validator
class is not overridden anywhere. Laravel version 5.2.45 Any ideas? Is this a bug or a feature?