The problem appears to be that the twist start for the chest is *way* too high. In Poser load M3 SR1, and select the Chest (1). Now go to Window>Joint Editor and from the drop down list at the top select Twist. As you can see from the line superimposed on M3's chest, there's only a very narrow transition area and this is why we are getting the shearing shown in the inset. Changing the Start value, currently .512 (2) to .463 (3, which is what the original M3 had) makes the transition much smoother (of course, it still looks odd in the inset because I haven't twisted the abdomen). You can save M3 in this state, run Dial Cleaner over the resulting CR2, and that should give you a usable figure until DAZ update the update to the update.

The twist end value is also different in SR1, by the way, but I haven't altered that. It does indicate that they were trying to fix the chest problems that have been reported.