Fallen order saw gerrera glitch

I'm playing jedi fallen order on the original xbox one. 

I've completed the game with no issues on the xbox one before, i started a new journey plus save this time round. I've gotten to the ATAT mission and my game constantly glitches on meeting saw gerrera, he ziplines up into nothing on the sky and won't load on the front of my atat. The audio is buggy as hell also and plays in sections n skips some lines of dialogue as I progress down the trench. I've tried 8 different ways of trying to progress past this. I've taken off the inquisitor skin, I've deleted my save from the xboxs HDD n tried reloading one from the cloud. I've played it off line and online, doing all or none of these things. I've done it with shared usage data on and off and nothings worked. I can't progress past meeting saw because he doesn't load properly. Is there anything I can do or has my game just been completely f*****d