@danilor welcome to the forum!
I moved your report to this existing topic because the problem and temporary solution are the same as reported here. The reason this happens is because you are running iNaturalist in Portuguese and the name of the country is spelled Brasil in Portuguese, but Brazil within iNaturalist.
When using the Location search on the Explore page, iNaturalist tries to look for a place called Brasil, but it doesn’t find the country, it finds Brasília, which it thinks is a closer match. To avoid this problem, please use Filters->More Filters->Place.
