Not in the contradictory sense, rather in the addative sense. Since they added a Deus Ex Machina, they needed to also add more lore in order for the Deus Ex Machina to be explained. This is really a minor "patch", one which is really only an issue once examined from the position that the Deus Ex Machina is a bad move. If you don't find the Deus Ex Machina to be bad (or even neutral) you would probably perceive the patch as simply being more lore (which essentially it is) rather than more lore with the intent to explain their Deus Ex Machina.
Now correct me if I'm wrong but you think that the god Vivec suspending the Moon is bad use of a Deus Ex Machina? So if this is not something a god should do, then what should a god do?
I wouldn't call it a whole other argument, more like the underlying basis. The two biggest in Oblivion were the Avatar of Akatosh (which is pretty much the literal example of a Deus Ex Machina) and the Colassal Black Soul Gem somehow granting immunity from Mannimarco. I have a list around here somewhere of all of them (I actually collected them for a thesis at one point), I'll see if I can't find that list again.
Very much agreed on both accounts.
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Edit: I should add that the difference with the account of Vivec and the Moon is though that there was no impossible situation that could no longer be resolved. It was very much an act of god, but not in the sense that it is used to resolve an impossible situation, one god throwing a rock at another who then suspends it above his city does not in anyway contradict the internal logic of the story. (As such, it's not a Deus Machina at all!).