It's not bugs per see it's basically a result of no dev intervention of any kind. World 5 was plagued with game breaking wall jumping and the fixes were few and far between. The game as a whole is flawed due to side effects of good changes that rippled. take for example curio system it's a great system much better than the old botting grindy shit yet it encourages alts to the max, the old nerfs on single strong chars that were good in a time when every char had to be brought up by hard work are now discouraging investment on anything but hordes of alts, the curio system also makes viable in conjunction with teleportation chars that are completely split from their centers of production basically leaving you absolutely no way to connect them to where it hurts them aka their real town. And vaults as we know them are stupid shit but it's how the game demands to be played right not so we're left with alts and vaults and no way to counter them.
"Since all men count themselves righteous, and since
no righteous man raises his hand against the innocent,
a man need only strike another to make him evil."