While the Halo: Reach beta is largely a blast, not everything is perfect. Thankfully Bungie knows this, and is letting us know the things that will be fixed by the time the final game rolls around.
Things like FLAG TAKEN...FLAG DROPPED...FLAG TAKEN...etc etc. It's annoying as hell, but has "already been fixed for fall". So too has a loophole on the Stockpile map that allows people to deliberately ruin games by messing with their own flag collections, along with isolated cases of graphical corruption .
Even some things that were design choices, and not glitches, are being re-tooled, like the game's reticules - which people think are to transparent - along with the amount of damage a frag grenade dishes out and an improved method for detecting where you're taking fire from.
It's a great game so far but it does need work. My main complain was their method for detecting where you're taking damage from. It was pretty much you can either see him or it tells you hes behind you. So at least thats getting fixed. All the weapons kind of suck too.