Had something similar but less dangerous recently: I “won” a month’s subscription to a brand new “high paying, not on the public sites” job board where if I wrote a cool integration I would make a bunch of money (except the fine print said they could just take it). It took about a minute and a half of playing with the API to see they hadn’t even bothered to fully trim the listings they scraped from other sites. Each job application required you to answer a fairly detailed engineering issue. Best I could tell is they stole your answer, applied to the gig and then did one of those bait and switch interviews with the actual company.