Ive tried wrapping butts, with the same results.
The pan slowed down the butt.
Next one I got my bark then wrapped in BP tossed it back on the grate
in my offset. Juice went to the bottom of the offset.
My next time I'll put a foil pan in the bottom of the offset.
Shouldn't affect smoking time, but I can retrieve the juices after
I remove the butt. Live and learn.