Hi ,
From what I see on my end this isn’t a bug. I can get accuracy that fits correctly around the spheres I have in my test.
In my test using at least 0.7 for accuracy results in correct convex collision generation. This may differ depending on the mesh of course.
As for time it takes to generate, this can be dependent on system specs and complexity of the mesh that the convex collision is being generated for. On complex meshes I’ve used in the past since this new method was introduced with 4.8 that provides more accurate collision generation and can take longer to generate depending on accuracy and hull verts.
While it may have appeared as though the editor froze at 95% it was still processing. You’ll just need to wait it out for the final results.
I hope this helps.