I think when UST drop until 0.6$ can't called again with stable coin because not have meaning and function as stable coin for UST with Luna network.
USDT also fell because of the FUD news factor due to spam chain messages sent via email, I don't associate with UST even though both coins are stable but both are stable experiencing the same thing falling from the price of $1.
I don't see any significant fall in the past 24 hours regarding USDT. Are you sure about that? Because it doesn't sound like a legitimate source. Anyway, back to UST, Do Kwon tweeted that he should be making an announcement on how to recover UST back to its $1 peg. While it has gone pretty close to that (higher was 0.95 if I'm not mistaken), it still struggles to go beyond that. I believe that action will be taken in order to save it.