JSFiddle - React, Tailwind, and code Playground

HTML

Funciona:
<form>
    <input type="text" required="" pattern="[a-z]{2,35}" tabindex="6" name="edtCidade" id="edtCidade"/>
    <input type="submit"/>
</form>
<hr/>
Não funciona:
<form>
    <input type="text" required="" pattern="[a-Z]{2,35}" tabindex="6" name="edtCidade" id="edtCidade"/>
    <input type="submit"/>
</form>