Last night I was doing an echo when the server updates were being rolled out. I decided rather then try and complete the echo at the time. I’d log out and do something else for a bit. Today I redid this same echo and it had a tomb in it. After completing the tomb it told me I couldn’t use its services or open the chest because it was a failed echo… I of course was not bothered by this, so I just portaled out. But the echo wasn’t failed as I had my rewards for completing still… so the tomb seems to flag an echo as failed should you DC or leave an echo unfinished(not die), while the echo itself does not consider itself failed.