I have found that Jack’s hijack no longer consistently makes the enemy explode if they survive at the end of the hijack. They will then explode once they are damaged enough later. This has happened with various enemies on various difficulties.
(I have filled out a support ticket).
If anyone else has this experience please post details here.
I have only done 3 successful master runs in horde. Can never get a team together. Invite me if you ever need a fifth. I don’t mind operating trishots.