Since you indicate that you had not experienced this prior, I am going to highly suspect that is lack of familiarity with the new rocker profile. You are experiencing what a lot of people report when first trying this profile.
These boards are very subject to pivot and any rotational movement of the upper body can cause this. Do you notice a tendency for the tail to skid out in front of you more than behind? Riding with open shoulders in a countered stance can really cause some issues here. One thing if you find this to be true that helps is angling the back foot out more. I have found that with this profile, a symmetrical duck stance works best. I run 15/-18 (my right foot naturally kicks out more so I have more angle on the rear foot).
Another thing I am finding about any full rocker or the C2 style is that you need to use some fore aft movements. You could be staying forward too much and not shifting aft when needed. This will keep the tail light and subject to skidding out. Start your turn by shifting forward toward the nose and as you go into the control phase, begin to slowly shift aft so you complete the turn heavy on the rear foot.
Play with that and see how it goes....