So to clarify. If you are now seeing that things have switched from Hull to Default that is because your data has been corrupted already and the property now reflects the truth.
The problem with the way the old feature worked was that there were 2 pieces of Data for Collision Fidelity. There was the “Collision Geometry” data, and the “Collision Fidelity” property data. Collision Geometry was responsible for HOW your objects were going to collide, and how complicated the collision was. There was one special case with boxes where this isn’t 100% correct, but since you are dealing with Hulls only for your case NOTHING has changed.
Anyway the bug was that the two pieces of data were independent from one another, which meant it was easy for Collision Fidelity to get out of Sync from the Collision Geometry data. Your objects still collided like Collision Geometry suggested, but the Collision Fidelity could have lied to you about what happened.
The change I made was to derive Collision Fidelity FROM the Collision Geometry, and simply use the “Collision Geometry” as a UI element that is user facing. Having 2 interdependent properties is bad coding practice, and that is my fault, but if you are seeing a problem now you’ve always had this issue and now it is just obvious that the issue is there.
You should still be able to select all objects and trigger a mass property change to Collision Fidelity “Hull” to fix this.