Was there something near the trap that they could get ahold of with their other front foot or perhaps set on a steep bank or some type drop off?

It's fairly flat. I do have it wired off to a small tree 8" or so wround so it may have tried to climb it but there are no lower limbs it could reach.

The aluminum dp that pcs outdoors sells are stout. I use those and old grizz ones that are super stout. More than once I’ve had possums lose whatever got caught without even leaving a catch circle. Usually I find the possum foot/toes in the trap, but Maybe something ate the bait and such out after that occurred.

You think maybe they climb the tree and jump out, hitting the end of the chain hard?

Anything is possible it's got about a foot of wire and the factory chain. It had originally grabbed it deep since its hide was scraped From it's elbow down. I'm just glad to learn what happened to the first one now. I'm always learning.

Maybe be I should start a thread about my missing beaver snair cable? The swivel was still there and the stop had been machine pressed.