Nick, yes, I tried several different power sources, all to Atik 11k specs, same issue.
I've binned this camera before and never had the banding - this is new. It appears to have started last Tuesday, Sept 17, judging by a review of recent subs. It occurs at all binning levels except 1x1 (at least I do not see it on any of the 1x1 subs).
Hopefully I will hear back from Vince or Rui soon and that this is something that can be easily diagnosed and resolved.