During mission "A Matter of Life and Death" when unshrouding in the south pool, it kicks you out of game instead of removing the shroud and allowing you to continue with the event.
Note 1: It dos not do this all of the time. Note 2: Classes with permanent Illusion AA encounter more bugs with shrouding than other classes. Note 3: Healer mercs go crazy when someone shrouds and has such a high HP pool, rendering them near useless. Note 4: Upon initial shrouding, the UI element may bug out and need adjustment to view/access tha abilities. Note 5: The event can be completed successfully. For RoF, this event (and raid) is one of the most despised. The other is "An end to fear" which is completely RNG at the very end.. whether you get the Cazic DT in a reasonable time, or it bleeds you out through attrition due to not firing or firing right before Xaric does his temp form shift...
Its been like that for a looooong time now. It gets annoying for sure. Depending on level doing this, you should only have to shroud 1 time (at the step it says to), def drop any illusions you all ready have, suspend your merc, and slowly allow it to swap shroud off you. Dont go hitting buttons or moving while it happens. Use Mage pets for the rest of the attacks on the named and his shades that pop. Mage pet procs dps him reguardless of his current form.
There is a known client crash when unshrouding caused by having a combat ability timer - might be this one.