After successful installation on Magento 1.9 pressing Enter in the search field returns 404

I installed the Algolia extension and configured it.

It works for the autocompletion, BUT it breaks when I press enter in the search field - I get a 404 page since it tries to load unexisting page https://www.mysite.com.br/undefined?q=

Could someone help me understand and fix this please?

Do we still have anyone here who could help on Magento 1? I know it is not supported anymore, but we have no other way than keep using it for now…