Here are the bugs I noted during the first beta weekend:
Some of the item icons were broken - they just showed a red square.
The Orc Assault event didn't seem to work. I tried multiple instances with no luck.
At one point I had a mouse-over bubble that said "Press F to interact" floating on my screen. I had to change instances to get it to go away. I tried to replicate the problem to figure out how it happened, but couldn't get it to do it again.
The Giddy Up quest never seemed to complete, even after I bought a mount. It would appear in my "what's new" (CTRL+P) list every level after 20.
The Seer jump rate is ridiculous. They were frustrating even if you were ranged, let alone melee. (Maybe not a bug, but it sure seemed hyperactive.)
Lots of random disconnects. No client or server lag or churn leading up to it either - just sudden disconnects.
Some of the dungeon "shinies" didn't work, even after using the appropriate skill-granting item. (i.e. after using a 10' Pole, I couldn't use an item that required the Dungeoneering skill) I'm not sure if it was a failure of the shiny to recognize that I had used the appropriate item, or a failure of the item to grant the appropriate skill.
Pathing in some of the player created (Foundry) modules didn't work. You would have to dismiss and then re-summon your companion to get them to keep up. Inconvenient at first, but "lethal" if you were in combat and your companion was stuck in a wall. I don't know if it was because the modules were made incorrectly, or because of a physics engine issue.
Some traps were buried in the floor and couldn't be disabled. You could see a red ring around them, but got an "out of field of view" error when trying to disable them.
Floor depth seemed to be a problem in general - there were many, many places where characters (player characters and NPCs) were walking knee-deep on solid ground.
When running up stairs, Rogues tend to bend over, almost to a point where their head is dragging on the steps in front of them. It didn't hurt playability or anything - just looks... odd.
When sending a companion to train, they would almost always stay gone after the timer had run out. The timer would continue to count into negative numbers until the companion finally returned.
I couldn't get into PvP via the PvP quest. Maybe I was doing something wrong - but I didn't spend much time on it trying to figure it out.
A few recommendations / ideas:
An inventory item lock would be handy - so you can lock things down that you don't want to sell. That way you can prevent absent mindedly selling something you were keeping for your character and/or their companions.
Map icon for the mail courier. (Maybe it was there and I missed it.)
More character slots.
Comments
For future testing if you notice broken things detail what they are for feedback. If done via other game reporting then thank you.