I'm not affiliated with Brian or NAUT, so I have no additional information than what is public. However, I think the wording of "quiet period" isn't just a coincidence, as it is a term used in the financial realm often. I can only assume there are legal details being worked out at this time.
Based on previous updates from BK, mainly the March update, he outlines 2 things he wishes to accomplish with NAUT:
"mining centralization and lack of a buyer of last resort"
I believe the "buyer of last resort" idea is the reason for legal details needing to be worked out, and the reason for the silence. In later updates he says they are in talks with an identified partner.
"The stability fund was our first answer to the buyer of last resort issue; however, we believe a better solution exists. We will be spending the next month in consultation with economists and academic partners to identify the best way to create a buyer of last resort that will be hard coded into Nautiluscoin."
I can't imagine how this will work, but that's the info we have to speculate on.