I was mucking about in Tovald's Crossing and diffused a Falmer wall claw trap with no problem. After I got my butt handed to me by 3 Falmer in an ambush I reloaded and got promptly killed by the trap because the game did not show that the tripwire was active again. It looked like a broken tripwire but behaved like a set one.

So..are you asking if this is a bug? Sounds like it, report it on the wiki.

Cheers

Yeah, I've seen that also. Luckily the first time it happened to me I was crouched so the trap went over my head after quickly scrambling backwards.