An update addressing an issue where Deathtrap can restore enemy shields has been released on PC, Playstation 3, and Xbox 360. After this update has been applied, Deathtrap will no longer restore enemy shields.
For update information, please visit:
PC: http://support.gearboxsoftware.com/entries/22126761--PC-Update-Hot-Fix-Information
Xbox 360: http://support.gearboxsoftware.com/entries/22147216-Xbox-360-Update-Hot-Fix-Information
Playstation 3: http://support.gearboxsoftware.com/entries/22127181-PlayStation-3-Update-Hot-Fix-Information-