from yahoo, and my iqfeed data, the close price of dgaz on Nov 29 and Dec 2 is 168.84 and161.39 respectively. I do not know where you got 164.75 and 161.93. 161.39/168.84-1=-4.4%. Yesterday at market close on IB TWS, it also showed -4.5% for DGAZ.
I sampled the close price for both of them at 4PM EST on Nov 29, but I guess it was a holiday and a short day, so my price came after hours. Anyway, this shows that the price on a holiday may be inaccurate, and who knows what else was going on. They could've been doing rebalancing, NAV might've beenm wrong earlier or wrong now. Or they might've not be able to balance properly due to lack of liquidity, especially on a holiday. This is what happened in Feb 2008 with SVXY, when it dropped 90% because they couldn't buy enough VIX futures and had to pay whatever price they needed to pay to balance their ETF, pumping VIX futures price up by their own buying. This stuff happens with all ETFs, especially leveraged ones.
So really, I see now that all that price movement in DGAZ came between 1PM and 4PM EST on Nov 29, which was after hours during the holiday. DGAZ moved a lot during that time, while UGAZ didn't move at all. The reasons may be as I stated above, though in addition there may be bugs in those ETFs and how they rebalance. Early ETFs had serious issues with rebelancing, and such issues can still happen, possibly due to lack of liquidity, especially after hours.
%% Typical 3x pattern; even if its not normal /that dramatic.Good market to blow up in; even a pro like T Boone Pickens went broke in nat gas co/debt...................................................................................