Friction issues in Upgrading from 3.2.2 to 3.3.x


I am working on upgrading an application from PhysX 3.2.2 to 3.3. A ring hanging on a peg that was visually at rest with 3.2.2 started shaking with the upgrade. If I change the friction model from the default ePATCH to eONE_DIRECTIONAL, the ring becomes visually stable with 3.3. With 3.2.2, the ring is stable with both friction models. It seems that something in the ePATCH friction model has changed in going from 3.2.2 to 3.3. Even though changing from ePATCH to eONE_DIRECTIONAL seems to solve the problem, I like to keep using ePATCH with 3.3 so that I will not introduce any other problems. Was there a change to the ePATCH friction model or to the default parameters? Please help.