343 has managed to fix the wayward projectile bug in Halo 2 multiplayer. Other fixes have also been dealt with. After some more testing the game should be patched in a week or so.
I mentioned earlier that the entire Halo package was replaced with the Halo 2 release. This was to take advantage of the fixes and then make it easier to update the game with a hotfix when needed.
Halo 3 is still crashing so there is lots more to do to get it ready for the PC distribution. There are even synchronization problems to fix. The crash is in Valhalla map and exists in both custom and matchmade sessions.
QA has continued testing around a series of bug fixes on Saturday. The fixes involved appear to have resolved the rubber banding, desynced vehicles, objects, missing effects, and eventual instability in long matches in Halo 3. 343 said their initial review of these changes show that these issues are no longer occurring in the Xbox One build.