I got my K24 a few weeks ago - did short ribs and pork belly burnt ends. Turned out pretty good but would go easier on the dry rub with the short ribs next time. I didn't let the temps settle in so initially it was steady at ~250, loaded up the grill and temp stayed around 225 for a while and I couldn't resist messing with the vents and it shot up to 300, finally coming back to 225-245 range (probe and dome temp).
So I would stay:
1. let the temps settle in for a while longer (I don't recall but I think I waited less than 20 mins so will aim for 40 or so). Resist messing with the vents if you have it tuned in to the right temps initially.
2. light your charcoal from the top so it burns down if you aren't doing that yet.
3. you might have a air leak somewhere After that cook, I did add a layer to the top vent and opened up the bottom vent with the intent to add some nomex but it made it impossible to close. So I removed it and tightened everything up and it seems more sturdy then it was before. I sealed it up with some Lavalock RTV I had around from my old smoker.