here is no need to be alarmed by this. In fact, we automatically generate a new address for you after every transaction you make or when funds are moved between your wallet and our cold-storage system. This is done to protect your privacy, so that a third-party can not view all other transactions associated with your account simply by using a blockchain explorer to look-up an address they know to be yours.
All addresses that have been generated for your account will remain associated with your account forever. They are safe to re-use to receive future payments, but for the prior stated reasons, we recommend using a unique address for all transactions. You can view your complete list of wallet addresses at any time here.