I had the same issue initially in my kk42 @Mcdddy. The worst time was when I was cooking 4 pork butts and I kept the KK open to wrap all 4. To make this as good as it can be (and I feel now I control temps really well) is modifying my procedure. now when cooking multiple pork butts I:
go ahead and rip off the piece of foil or butcher paper on my side table
open the grill, grab a pork butt, and put it on the butcher paper
immediately close the lid
finish wrapping the butt.
Put down another piece of paper/foil
open lid, put the wrapped piece back on, grab another one and put it on the paper
immediately close the lid
repeat
In other words if you keep the lid open as short of a duration as you can, it'll be much better. Leave it open the whole time you are wrapping and your temp may spike +100 degrees and be difficult to bring back down (at least this is my experience).
Like other folks posting, I don't mess with my cooks much at all.
Billows goes on from the beginning. Before putting food on at 225 I make sure the grill has been fully heat soaked. With the KK42 that might be 90 minutes. Once I put something like pork butts on I don't even open the grill for at least 6-8 hours (or more! - with a pork butt sometimes I don't even wrap until resting!)
But when I wrap I follow the above procedure and it definitely minimizes the temperature jump. I still sometimes see my KK go up from something like 225 to 250 after wrapping but to me that's not much. Also sometimes the foil produces more convection so it can read a tad higher without having anything 'wrong' or 'different'. If you're wrapped and you're probing the meat, then to me 25 degrees is no biggie either way.
The KK keeps so much moisture in, one thing to try is just not wrapping, especially if you're consuming immediately. I vac seal mass quantities of pork and when I am doing big cooks I wrap just b/c it creates a little more consistency (and the bark isn't as good when it's not fresh).