Numerous issues when manipulating destructibles.
1) Changing collision response pre-fracture will not affect chunks post-fracture
2) Changing collisions response pre-fracture will prevent damage from being applied from impacts (using ApplyDamage directly will still work fine)
3) SetSimulatePhysics will not have an effect on a destructible when called in either BeginPlay or the first tick after spawn
A demo project from the licensee has been provided containing four failing test cases for these issues.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-22171 in the post.