I've seen this several places recently, and the newspaper today was the last straw. People of the English-speaking world, "illusive" does not mean the same thing as "elusive."
Elusive means something is hard to capture or find. Think of nature documentaries where the narrator says, "Ah, a rare sighting of the elusive red-throated grottlenose titmouse." Illusive means illusory, not real; "The titmouse proved to be illusive, being merely a holographic marvel designed by my archenemy."
In today's final straw, the newspaper reported that cougars are menacing the tony town-within-a-city of Belle Meade (it's where Nashville's celebrities actually live). The headline said that solutions were illusive, suggesting the mayor had tried several that failed. This led me to wonder if the town leaders were gullible or if the cougars were particularly hard to eradicate. Instead, the article revealed they had not yet come up with any solutions to try.
That's animal cougars, by the way, not the new slang cougars. (Which is a horribly misogynistic term that needs to go away.) Or at least I assume, given that shooting them had been discussed.