Is there any chance you can email us your project file along with exactly what steps to take to cause the crash? contact@esotericsoftware.com I realize some bugs don't happen every time, but if you can do this, it would greatly help us to fix the problem.
Otherwise, we have done a lot of work on how meshes work under the covers in Spine v3.3. Meshes, bounding boxes, and paths are work in a similar manner, so in 3.3 they share the underlying foundation which should be more stable.
