There are few things more malicious a senior engineer at UL can do - than to raise this issue at a lunch table of new engineers. Trust me, it's almost an official 'lunchroom sport' over there!
You see, the wires are NOT twisted for the testing- so the question becomes 'does pre-twisting violate the 'listing and labeling?' Ultimately you reach the same point you do when someone makes a hole in a box: we just don't know.
An alternative approach is to return to the basic concept that all splices will be mechanically and electrically secure. When you pre-twist, it is the twist that accomplishes this, and not the wire nut. The wire nut is simply an insulator at that point - an alternative to yards of tape. The key here is to recognize that the twist is the connection, not the wire nut. The wire nut's ability to hold the wires together becomes academic- all you need is for the thing to stay in place.
Are you failing to take advantage of the full potential of the wire nut? So what if you are? It's a 'suspenders AND a belt' sort of thing.