It seems that choice scarf doesn’t always work on the latest version. I learned this on the worst way posible in a nuzlocke run as my non-negative speed nature lucario and non-negative speed Delta scizor were outsped by Calreath’s Heliolisk, even tho Both were scarfed. I could posibly understand the heliolisk outspeeding scizor as it could randomly have a +speed nature and speed IVs make outspeeding plausible, but there is no excuse for it to be faster than lucario, both in game and in the wiki the heliolidk carries a life orb, no scarf
was your lucario ev trained properly? uninvested scarf lucario without a speed boosting nature gets outsped by max speed heliolisk, not accounting for level differences.
Whoops sorry, i hadn’t seen that hard mode gives favorable nature to boss battles (although to be honest they don’t mention the types of nature in the wiki)