A bug was reported in the game, which allows to play 2 characters from one account on different servers at the same time. We took a closer look at the whole thing and could exclude serious problems.
The simultaneous login of several characters of the same account on different servers should not cause problems with other characters or the account itself.
The error will be fixed in a future patch. Until then the possibility to log in simultaneously remains open.
As soon as we have more information for you, we will inform you about it. A hotfix over the weekend is not planned.