LG Issues G Watch Update To Alleviate Skin Irritation Issue
"Recently it has come to our attention that a small number of G Watch devices have been reported to have developed discoloration and residue buildup on the terminal pins located on the back. While completely safe and unlikely to affect charging, LG will be rolling out a maintenance release over the next few days that will disable the current when the G Watch is not in the charging dock," an LG representative told Android Police. "The maintenance release will be rolled out automatically over-the-air to all G Watch owners. We thank G Watch users for their patience and apologize for any inconvenience this may have caused."
This is one of those instances where science is fun (or not so fun, if you've suffered skin irritation). What's been happening is a chemical process that occurs when an electrical current travels through two different materials (usually metals) and an electrolyte. In this case, that electrolyte is human sweat. The end result is galvanic corrosion.
What LG's update does is disable the current while the smartphone is not connected to its charging cradle. With the absence of current, there no longer exists a chance for the chemical reaction, which itself was leading to minor burns and discomfort.