I don’t know if I already posted these…
Infection Bugs
If a Human joins after the round starts, their alliance status may be glitched. Specifically, they show up to all players – even fellow Humans – as an enemy. They even grant aim assist! If the glitched Human is killed by a teammate, however, it still counts as a betrayal (though the killer will not hear the announcer say “Betrayal!”); even so, the glitched Human is liable to die several times without knowing what’s going on, and their teammates are liable to get booted before they figure out what’s happening.
If a Human joins right as the Last Man Standing is killed, the newly-infected Zombie will keep the LMS waypoint, and the joining Human will not receive a waypoint or the medal. I do not remember if they receive the LMS traits, but I doubt it.
Sometimes, certain Player Traits will desync. For example, I’ve had many games where as a Zombie, I don’t see any of my allies’ waypoints even though the settings state they should be visible. As a Human I’ve also seen (and been infected by) Zombies without Forced Color (even though the gametype had it set for them). This may be an incomplete manifestation of the alliance status desync bug listed above.
Everyone knows this one by now, but: if there is only one Safe Haven currently on the map when the game tries to select a new one, it will fail; no Haven will be selected, and the announcer will repeat “Hill moved” until the end of the round. I am not sure if this changes should a new Haven spawn in after the glitch has started.
Stockpile Bugs (may exist in other gametypes)
If an Armor Ability is the STP_GOAL, its visible boundaries may desync. Specifically, if the wearer dies, the location of the AA will desync (as it is attached to a corpse, and corpses don’t sync in multiplayer). This will in turn cause the visible boundaries of the goal area to desync, although the goal area’s real position is tracked accurately. The desync is purely graphical, in other words. This could possibly be fixed by syncing corpses whose equipped AAs have gametype labels.
Forge Bugs
A manually-entered set of rotation values is converted back-and-forth by the game engine. If you enter an irregular (non-snap-based) set of values, release the object, and then reselect it, the values will be converted from the set you entered into the game’s internal representation, and then back again. In fewer words: what you get isn’t always what you gave. This can make the construction of structures with complex rotations (i.e. optimized circular towers) unnecessarily complicated.
Delete All Of These only deletes items if they are of the same type as the selection and if they have the same gametype label. This makes the function indescribably useful for deleting lost items without sacrificing others of the same type, but makes it less useful for its intended purpose. It would perhaps be better to have two functions; “Delete All Of These With Same Label”, which keeps the current functionality, and “Delete All Of These” which actually deletes all of these.
Possibly as a consequence of the above bug, Rotation Snap can break and rotate an object several times what the snap was (i.e. an object snapped to 90 only being movable to 0 or 180). Rotation Snap is also highly unstable when the Edit Coordinates dialog is opened.
Often when rotating a large Forge piece, one may be inexplicably forced through the ground and killed immediately. This can happen even when you grabbed the piece near its center of gravity (meaning that you shouldn’t have moved more than a couple of feet).
A massive amount of physics lag can be caused by placing two Grids into a map’s hardcoded terrain and setting both to Normal physics. The lag is so intense that everything slows down – even menus – to the point where “frames per second” isn’t as accurate a phrase as “seconds per frame”. As you can imagine, troublemakers can do this when in Forge with others, and it becomes extremely difficult to boot them when they do.
File System Bugs
Complete and total loss of Campaign data is a very common complaint. Armor data (stored client-side) is usually also missing, though it generally syncs with the Matchmaking servers and hence it’s rarely, if ever, truly lost.
There are many cases in which the database gets “confused” when saving a map. Generally, the result is that when selecting Map A, the game instead loads Map B. Map A becomes completely inaccessible and unusable.
The “Save” command in Forge is either broken or insanely counterintuitive. Let’s say that you open “Map C”, and use “Save As New Map” to save it as “Map D”. You then make a few more changes and use “Save”… but it is Map C that is overwritten, even though you are now currently editing Map D.
The entire file system loads files slower than my years-old, not-a-current-model iPod. This is despite Reach having the processing power of the entire Xbox 360 powering it. My copy of Reach has to sort less than 270MB of files, while my iPod has to sort well over 1515MB of music. Reach is doing less than 17.8% of the work that my iPod is doing, and hence should not be the slower of the two.

