How do the native / introduced / threatened filters work in Explore?

I’ve been trying to explore the plants in my area, and I’m very confused - I have “introduced” and “verifiable” checked in my filters, but there’s still a bunch of stuff with the N - Native designation coming up in the search, and even a few E - Endemics as well. I’ve checked the species page, and they do seem to be correctly flagged as native, so I’m very confused. Does it include species that are invasive in other places, even if they’re native within the search area I set? And if so, is there a way to filter those out?

A similar thing happens when I select for “Threatened” - it pops up a bunch of invasive species that I guess are threatened / endangered in their native ranges, but not so much here. Is there a way to search just for local species that are threatened?