This seems like a bug. I assume that specific words are coded to not be capitalized (e.g. and, of, the) and those would have to be specifically programmed for each language?
Other cases might have to be dealt with by negotiating the different place names; I can imagine there are a number of species that are called different names in different Latin American countries (just like species with different names between North America and the UK).
I get the impression that Spanish common names need quite a bit of curation work, but I’m not really comfortable wading into that without being fluent.
Probably the solution here will end up being to make a flag on each species that you find issues with, to start a discussion on fixing the names. There’s a tendency to have discussions about removing or fixing English names on certain taxa, all while leaving the names in other languages that have exactly the same issues…