Diablo 4 Patch 3.0.4 - TL;DR
Small patch yesterday with six targeted fixes. Two of these are ones you'll want to know about.
Socketed Runes and Gems were being destroyed when recycling a Unique item in the Horadric Cube. Fixed. If you lost Runes or Gems to this before the patch, unfortunately they're gone - but at least it won't happen again.
Bloodwyrms from the Hellmouth War Plan modifier in Helltide were dealing massive damage even without the Bound by Blood node active. If you were getting randomly obliterated in Helltide with Hellmouth active, this is why. Fixed.
Greed is Good portal exploit - The Path of Coin portal in Nightmare Dungeons could be activated multiple times per instance, and could also trap players if they teleported out and back. Both fixed.
War Plans progression could get blocked if you disconnected while claiming rewards. Fixed.
Of Void and Vessel quest could get stuck if you died during the final boss or killed the First Midwife before the objective triggered. Fixed.
For the full patch notes, check the official Blizzard post.