You always need to ‘tune’ these traps before they go into the ground.
Set them and test them by pressing the trigger as the mole would, it should fire with only a little pressure. Sometimes this can be achieved by bending the spur on the trigger up a little sometimes shortening the spur, sometimes both. Occasionally the ‘dog’ is twisted-it should sit horizontal when set. Only tweak a little at a time otherwise you will get the situation where both fire when one side is triggered.
Once you are happy go and set them. As you start using these traps use the trap as a template to gig the hole just big enough to get the trap in. Get down to the level of the pipe, then use a spoon or ice of wire to clear any debris from the pipes and then press the floor of the opened pipe so that it is as you would expect the base in a tunnel to be, not packed solid but flat.
Place the trap in pressing so base of the trap loops are just below the soil in the floor of the pipe, not too far or you will bed the triggers in and cause the mole push against it without it firing and causing it to bung it up or dug under, the trap loops need to allow the mole to enter without detecting the sides or the base that should be sitting just below the soil. The trap needs to be covered over and firmed in so that it is stable with no movement and so that no light or drought is able to get in.
Hope this helps.