Ok, I have a temporary fix that I have tried and tested. Whenever you run into a mission that freezes, no matter how many times you redo that mission, its going to freeze. What I found is that you just have to load the autosave and MOVE ON TO ANOTHER MISSION and so far 100% of the time that other mission will be perfect. This also means that you will have missed that mission. Also means that if its a story critical mission, I don’t know how to progress.