I don’t believe its DST related. I’m assuming this is the patch that you were referring to that fixed it?
They stealth added that in a few days before they announced it, and it doesn’t even follow their own text, since the only thing that’s resetting at 7:00 realm time is which dungeon quest is active. The active daily quests for everything else still rolls over at 3:00 server time (handy for when you want to skip an annoying daily like the blood in the water cooking daily), and locks for dailies and dungeons reset at 11:00.
But regardless, that patch did nothing except shrink the window for your second bounty satchel from 3:00 - 11:00 ST, to 7:00 - 11:00ST.