So, during a recent crash, my palisade gate was left open, and my key lost. So, I thought "No problem, I'll just put on my bear cape, wield my trusty pickax, and bash the thing down." Didn't work. Apparently, if a gate is open, you can't destroy it. You just walk to the middle of the gate and sit there, looking for some solid object to destroy. No stamina drain, no chopping sound, nothing.
Another bug: while trying to come up with possible solutions, I noticed that it was possible to build a gate inside of another open gate. Gathered the 30 blocks, and built the gate, got a new key, and thought "problem solved." Nope. First time I opened the gate, for some reason it put the old gate on top, so I can't close the new one, even though I have the key.
I've got a temporary solution of building another small stretch of wall and a new gate in front of the others, but it requires that I expand my claim to cover the new addition(which not all folks would have the opportunity to do if another claim were nearby), and really messes up the chi for the place.
Not exactly a game-breaking bug, but something that should probably be fixed sooner or later.