: It was easily noticeable on "The Arbiter" for me. I played a
: looooot of Halo 2's campaign and the Elites never behaved like they did on
: my play through during the H2A version (staying in place and not following
: or running head first into battle and just getting torn to ribbons despite
: their low health and shields.)

It was so obvious on Outskirts, Metropolis, and The Arbiter for me. On Outskirts in the final tunnel section, I got out of my Warthog and the Marines disappeared. As I headed for the exit those two Marines had a ridiculously impossible lead on me on foot. On Metropolis, the Marine on the bridge with the rocket launcher just ran around my Scorpion. When I got out to playfully nudge them with my fist to get on, the original two Marines who were already on just disappeared entirely. On The Arbiter, which I had played a few times, the two Elites at the beginning always met their doom at the hands of the Heretic Grunts on that large sloped ramp.

These glitches or bugs or whatever are really pissing me off because I value the support of my allied companions. Their playful banter is always fun to hear amongst a sea of explosions going on. Playing alone is just kinda boring.