Talismans
I found out that I can't use active skill from talisman for increasing p.atk. I used that buff once and It worked correctly, but when I wanted to use it again (5 mana remained) It didn't work (I didn't get buff).
Daily quests
Read other forum topics. 60+ Daily quests doesn't work. I can take only 1 DQ and other ones I can't.
Debuffs
I don't know if this is bug or normal game feature, but it seems to be very illogical. I received 2 the same poisons from mobs at the same time. My friend received 4 the same poisons at the same time.
How could somebody get 4 the same poisons, 3 bleeds,... at the same time?
Addition information: I wrote petition in-game about debuffs, but I got answer something like: "We are not here for answer this type questions. Ask your friend." I think it's serious so I posted it here on forum.
Talismans
I found out that I can't use active skill from talisman for increasing p.atk. I used that buff once and It worked correctly, but when I wanted to use it again (5 mana remained) It didn't work (I didn't get buff).
Don't know about the rest, but this could actually be "working as intended". Each time you use the skill on a talisman, it eats up a certain amount of the remaining mana on the talisman. So if your talisman does not have enough mana left, you cannot use the skill. So not only does the talisman use up mana (1/minute) when you wear it, using a skill costs ADDITIONAL mana.
For example, when I still played my SE main, I used to have some talisman which gave me an "invocation"-type skill and another one which instantly filled up all my mp/hp. The full mp/hp recovery one use around 30 mana each time I used it, so I could get around 2 skill uses out of each talisman (if I immediately unequipped it after using the skill). When after the 2nd use there were still around 10 mana left or so, I could just delete the talisman, because it was useless (not enough mana left to use the skill again).
The double berserker buff might be also not a bug.
Note that Vampire Warlords use AoE berserker buff (so it's a different kind, which all of the vampires around receive) and the Vampire Warrior has it's own Berserker self buff, that's why he is the only vampire with two of those buffs.