Why I see upper case into cell edit when typing?

Let me explain, when I type, the letters are shown in uppercase but when I remove the focus from the editing cell, the real letters appear without any uppercase effect, how can I solve this?

PS: Apparently I do not have any configuration that does this.

Please, check some custom applied on your page.
If the problem still occurs for you please, provide a complete demo, where the problem can be reproduced locally.