Hi,
Thanks for the project. It seems like the hitches/freezes you’re seeing are due to the objects becoming embedded in each other which can lead to the physics engine not knowing how to perform de-penetration. This looks like its mostly a result of solver instability. Because you have two large opposing forces acting on the same pair of objects and they aren’t dissipated by the initial collision, small inaccuracies can build up in the simulation culminating in the objects becoming embedded in one another. Without CCD, these objects may end up passing through each other entirely. The new interface may have exacerbated this instability, however it would have been there either way. To improve stability you may want to consider reducing the strength of the competing forces and/or reducing the contact time. The physics engine relies on small time-steps for accuracy, so increasing performance, or enabling sub-stepping with decreased delta time and increased iterations, are also ways to improve stability.
Cheers