take a look at step 19 on the ifixit ipad teardown... http://www.ifixit.com/Teardown/iPad-Teardown/2183/3. notice the soldering. probably a manufacturing problem on certain lots.
"Dont worry, the capacitor near the lower right corner of the Broadcom chip didn't come that way. The solder melted and it moved when we heated the steel casing to remove it."