Hmmm, that is weird. I asked our MR technician to re-upload the file to the server but the error persisted. Is it possible to determine which volume was missing for the 3rd echo? If it is the last one I may be able to drop the last volume for all 3 echos.
I don’t know. I might try opening up the first echo in a viewer and try to find a volume transition where there’s visible motion. You can then open up the same volumes for the third echo and see whether they align better as-is or shifted.
Others with more multiecho experience might have a better idea.