played a 0% wagering slot and then bonus got removed after i won

So I found this new slot on a crypto site that showed up as 0% wagering contribution for bonuses, but I just wanted to mess around and hit a decent win on it. After that, my bonus balance vanished, like poof, gone. No message, no warning, just not there anymore. Checked my history and it shows my last play and then bonus removed right after.

Now I'm just sitting here wondering if playing those slots at 0% really triggers something, or if they just saw the win and yanked the bonus as a rule. Has anyone run into this? Starting to think it’s not even about the math or the risk, just some secret casino roulette where my odds are dodgy in a different way. This one definitely has me triple-checking the fine print instead of my game stats.