when you say find you're meaning ID. when i read find i took it to mean spot 'a' trap that is a decoy but not know that it was a decoy.
i have to say that mine is working like yours and i took it to be as planned. recons are not the bomb experts. the engineer is. i figured the recon moves through and points out the trap. if it knew it was a decoy they would be useless to place. besides i'd rather run over a decoy and save time rather than spend time disarming it. but since my recon doesn't know my engineer has to come in and disarm counting down time off the clock.
but i would be interested to know which way they are supposed to work.