Having judged concentrates, including at one cup, my impression is that shatter is much more likely to end up with residual butane, than wax is, because of the much longer time under vacuum processing into the wax.
The thing that was made clear to me, is that all of the entries paid a $1000 to enter, thinking they had the winning extract, and all but one was wrong.
All felt theirs would pass the lab tests for residual solvent before plunking down that $1K, and a number were wrong there as well.
I personally think there should be different standards for the different solvents, because they aren't all created equally toxic, and in the case of butane, relatively non toxic in the amounts typically found.
The way many brothers and sisters leave butane in their shatter, is by processing at too low a temperature for it to readily escape, but for longer periods. That is why we use 115F for a shorter period, that still retains adequate monoterpenes.