I had a serious issue in HALO:CE in this TMCC, when “Save and Quit” option used, i found that if i was half way through a level, in this case “343 Guilty Spark” after the flood hits, i had to leave for work and after reloading up i found that i had magically completed the level and moved on to “The library”. Admittedly this has happened just the once and i’ve not seen this happening so far through Halo 2-A. Other than that, i notice invisible elites aren’t often invisible during first sighting and some AI are invisible completely once engaged in battle, Flood/Brutes all of them. Seems we all have the issue with friendly AI deciding not to join the hunt every level either :-|. Other then that, great game 
Funny I found this post. Last night I just started 343 Guilty Spark but decided to go to bed. Today upon resuming the game, it also put me in The Library mission and it shows I completed 343 Guilty Spark. WTF??
Audio Cut Scenes & Guns not working & Achievements not unlocking & Save and Quit does not work & Skipping Missions…