Somehow this bug hasn't made it onto the forums yet, but I know that numerous bug reports have been filed. The bug happens only after the team splits into two groups, the "top" group, and the "bottom" group. On the bottom group, there is an archer boss who summons Welwas. If the group wipes on this boss, HE WILL NOT RESPAWN, and the group will be unable to progress in the trial. Right now there isn't much outcry about the bug, but now that the weekly is Veteran Hel Ra Citadel, I have a feeling there will be lots of protest in response to this glitch. This has not happened only to my group, it has happened to all sorts of trials groups on more than one occasion. After the bottom group wipes, the boss simply will not reappear, and the lever leading to the next room will not open. Please fix immediately, or else most groups won't be able to complete the weekly!