When I threw a TRAPPED chest into the air, it starting blinking like mad, kind of like a hologram. I tried it with other blocks and items, but it only seemed to be the trapped chest malfunctioning.
Normally, it's supposed to just render normally in 3D.
1. Place the trapped chest in your inventory. It doesn't matter where you take it from (ex. Creative inventory, chest, etc.).
2. Throw it into the air, on the ground, or at something. Like mine, it should blink rapidly, like a hologram (tried to get a pic, but it just took a picture of when it was "solid").
EDIT: For some reason, it began to flash in the creative and survival inventory, too. When I placed it, it became this weird all-white block (see attached image). It continues to do this off and on.