Could Germany be attempting to liquidate or reconfigure its holdings on exchanges? Are there any other possible reasons?
Recently both United States and Germany were on news that they are sending money to centralized exchanges. The main reason would be that they want to sell the coins for their fiat in return. The governments can not be trading. While the exchanges can not disclose what the government do with the coins transferred to the exchanges.
Recently German government transferred 1700 BTC to a wallet. Which means they can hold the coins themselves. I guess that those 1300 BTC would have been converted to their local currency by now or would be converted later.