Duplicate simblos (+/-) in product quantity

Hello there!
I bought this theme to use with FooEvents plugin, as you can see here: https://progressivewebapp.com.ar/

But i have a problem in the product pages, as you can see here: https://progressivewebapp.com.ar/producto/entrada-de-prueba/
Screenshot: https://progressivewebapp.com.ar/scr/cantidad.png
Also in mobiles, the +/- it doesn’t show up

What is happening?!
Thanks!

Ticket