I have just looked at the cover of my Season 6 dvds and Daniel is not on it. So I guess this is not temporary.
I can neither confirm nor deny that I have knowledge of any such changes, nor their duration, nor would I be at liberty to discuss them if I did, in fact, have such knowledge.
However, there is a piece of unclassified information that relates to Meridian
Demon Core Wiki
Playing with a plutonium pit can be quite lethal.