Halo 2 Campaign bug

For over a year, a friend and I have been trying to finish the Halo 2 Campaign on legendary, and on certain missions like the Oracle and Delta Halo, upon completion of the mission, the game glitches us out when we finish those missions, we’ve tried everything from ensuring our internet connection is solid and restarting the game as well as redownloading the game and every time we try to complete the mission together. the game closes the campaign at the mission and beginning of the next mission’s cutscene and says “your connection to the game has been interrupted”. Please 343 help us or give us a patch to debug that issue.