It seems to only ever happen in the Orchard, but changing zones and going in/out of tombs will render my character invisible(not like the spell).
It was said to be fixed in one of the release notes I read before but it is still happening to me, Orchard only. Possibly they found an issue somewhere else that got fixed and not the Orchard...
It's been reported but I'm curious if this is something widespread or just happening to me... it doesn't seem like others I group with get it and it's a fairly new occurrence.