I have a monitored system w/service based on Alarm.com.
There are four (4) 2GIG-DW10-345 Thin Door/Window Contacts in the system.
One of those contacts will not trigger consistently once it is applied to the metal-skinned wood door in question.
All three other contacts are affixed to the same style/manufacturer door type and work without incident.
I thought the contact was faulty and replaced it with a new one. The new one tripped without hesitation before affixing it to the door. Once attached, it will not trip consistently.
Environmental attenuation due to metal is very common, and if you have a location which does not permit good signaling for the DW10 there are a couple options to resolve:
Try to re-orient or physically raise the DW10 from the metal surface. Sometimes only a little bit of distance is needed to be the difference between signal and no signal, but keep in mind this may not be as reliable going forward and I would recommend one of the other two options.
Use a different, larger sensor with a larger or raised antenna. Something like the RE201, while not quite as attractive on the door, may have a better signal than the DW10.
Use a repeater. The RE524X or 2GIG repeater can help significantly boost signaling when you have some sensors having trouble reaching the panel.