Something fishy going on with that skill. Have had it go off 20+ times on a mob in a few seconds. Not sure how to reproduce it. Haven't seen it do that versus a player, but if it does, you can be sure that will be the exploit du jour.
Had it happen to me as well. I was just standing in it not doing anything. I was wearing the reactive armor set thankfully and it did very little damage.
Anyway, it went off around 15 times in rapid succession.
Here since Beta.
Characters: All of them, both Stamina and Magicka.
Here is a screenshot of the trap firing more than intended:
Tool Tip:
The trap takes 1.5 seconds to arm and lasts for 1 minute. After being triggered, the trap resets and can be triggered one more time. Trap rearms once after firing.
Seems people discovered the bug on live.. good ball on ZOS on leaving yet another exploit in the game for more than a month. Why did we even test this crap on PTS?!