I just received this message from the Illinois FLL...
Teams:
LEGO Education has identified a circuit error in the LEGO MINDSTORMS Education EV3 rechargeable battery. The error does not in any way relate to or impact the EV3 programmable brick or the charger/transformer.
The majority of the batteries that have been distributed do not have the error, but every battery in stock is now being retested to ensure it charges properly before shipping to customers, and new supplies are being sourced. Customers who have received a rechargeable battery that has this error will be provided a replacement free of charge.
A message to teams who have purchased the EV3 with instructions on how to proceed is provided at this link:
www.firstlegoleague.org
We apologize for the inconvenience and assure you that LEGO Education is doing everything to resolve the issue.