Here's a graphical bug. Sometimes when you open a chest, the items will fall on top of the closed chest, and the Open Chest button remains there. Pressing it again will open the chest and cause the animation to replay.
Yup, got this as well. Chest opened by itself, shut instantly - items visible outside just like above. First map of Highway Robbery. In 2nd map of Highway Robbery chest bursts open and closes, no visible loot. Loot drop when opening as usual. 3rd map - I open the chest, it slams shut. Open again, loot drops. 4th map - same as third. All this sounds load related.
I've seen this bug today as well. Another chest bug from today: click open chest button, hear the open chest sound, it animates open and then switches to a closed view with no loot shown. I have to click it again to have the loot actually drop. I'm guessing it's related to the lag/server load that's going on.
I got this bug plenty of times before, its usually due to my connection and a large enough latency (1000ms). Something like it register the click on your client but then the sever says no etc... (Edit: I mean during beta when my connection is bad)