Half of general chat is missing, you can see only half the conversations most of the time. Also, you have to be messaged twice by someone in order to whisper them back, or to add them to your party because it doesn't come up with the server name like "[Saythe - Arthas]" So you'll get ppl whisper you saying "i'll go" but you can't actually add them cause you don't know what server they are on.
A HUGE Hunter glitch happened last night (10/10/2012). Okay, we're supposed to start off with Aimed Shot(A powerful aimed shot that deals 280% ranged weapon damage plus 6603 to 7356.), the reason you know this is the little passive that gives you a 75% increased crit chance with this if they are above 90% hp. Well keep in mind the tool tip you see there. Chimera Shot(An instant shot that causes 210% ranged weapon Nature damage plus 1246, refreshing the duration of your Serpent Sting and healing you for 3% of your total health. Should be used any time it's available cause it's your SECOND most dmging shot...well supposed to be second according to the TOOLTIP! At about 7pm last night, my Aimed Shot started doing 50% less dmg...I was critting for 20k at level 74 with this ability, I dinged 75 and suddenly, even though the shot got even more powerful on my tooltip end, it started critting for only 10k...my chimera shot crits for 9k, what's that tell you? At MY current level, Aimed shot reads **A powerful aimed shot that deals 280% ranged weapon damage plus 15,845.** now, since this skill's BASE dmg is the 15845...you take into acct armor, It should NEVER CRIT for less than 15k...cause that's not even adding the 280% weapon dmg...yet, i CRIT for 10k with it...and Chimera and Arcane shots, all crit for their tooltip'd dmg. So, in-other-words, I went from critting with Aimed Shot for 20-21k at level 74, to now being level 80 and I crit for only about 10-12k...something happened.
These are just a few bugs i've noticed since MoP released.