Not sure about Druid-secret-passage chest ...
But you can disarm the Blacksmith chest trap, by simply using some source of fire (or at least you could in previous patches ... didnt try this time) ... just note its smart to move that explosive barrel next to it first.
Druid trap: Add the barrels to your inventory, move them outside the range, drop them. The. Open the chest. The most damage I’ve taken was 7. Still need the disarm to work.
The Zhent stash in the Underdark is trapped, and disarm works perfectly. Not sure why the others are messed up.
+1
