Doors Fail Silently for Bottom-Block Links

[SenseiKiwi]

I'm not sure if this issue happens all the time, but I had to help someone who had a door that was slamming shut in his face. He had used a Rift Signature to link two locations, but his Nether-side door wouldn't work. It turned out that the door was attached such that the link was in its bottom block, not the upper block. The door should have worked anyway. No errors were coming out on server or client side. We must have overlooked a detail in supporting those kinds of links.