Hi there!
This is a common occurrence for WordPress websites and specifically for home page title tags. Google will often show different variations of titles or completely new titles based on the searchers intent. It makes sense if someone is searching your brand name but it can become frustrating when you want valuable keywords towards the beginning of the title tag instead of your brand name.
Some people argue that this doesn't affect rankings, as in Google is still indexing your proper title tag but is just choosing to display it differently. I personally think the opposite. I've gotten this problem fixed before and have seen better ranking results.
With that said, I would try different variations of your current title to see if Google will accept them. Something like: "TV Online | Assistir Filmes | Notícias | Futebol - GogsTV" or you could work the brand name into the title like "GogsTV Online | Assistir Filmes | Notícias | Futebol."
Hope this helps!