Navbar bug with Spanish tildes

[BubuDavid]

Hi there, I am working with this template but I am building my page in Spanish, so I need to use tildes, for example, introducción, guía, etc. But there is an error in the navbar, when I put these words, the letter next to a tilde changes to uppercase, like this:

As you can see here, this only happens in the navbar (see the red markers and the blue markers).

I wish you can help me with this.