Agreed. If the point of your question is not to find out the limits of the Mechanic's 'Energy Shield' I cannot help but think that has been answered. It absorbs damage via temp hit points, be it from laser, life leashes etc, the end result is the same unless there is something that states differently.
There is nothing in the books that state that a particular damage circumvents it, nor is there anything that makes it particularly overpowered when compared to other classes skills, Tricks, Exploits or Improvisations etc.
If you feel this Mechanic skill is too 'Over Powered' for your game, you need to follow the age old advise and actually 'Talk to the player'.
Let them know that this particular class feature is by your estimates too over powered for you campaign, and if possible let them know what else in this game may be 'Over Powered' so they do not make the same mistake again, after all, having 2 mechanic tricks out of 5 rendered un-usable is kinda of a big thing, but having that occur again with the same character is cause for reasonable irritation on the player's side.
