Mandatory fields ignored

Hi guys!

We are testing Hubspot forms, we have one here:

And sometimes the leads we get 2 fields are completely empty, “Número de teléfono móvil” and “Unidad académica”, which both are mandatory, any insight/solution to this?

That shouldn’t be happening. Could potentially be a bot getting around the filters, but I wasn’t able to bypass them on that page with any of my efforts.