From the bitcoin.de FAQ:

Code:

As soon as you have created a sales offer at bitcoin.de, the respective amount of Bitcoins is marked as reserved balance and cannot be used for any other sales.
If a buyer was found, the seller can no longer have the operator disburse the sold Bitcoins.
The Bitcoins remain blocked for the seller as well as for the buyer until the buying process is completed;

To be found here: https://www.bitcoin.de/en/faq/what-does-bitcoin-de-do-to-offer-security-to-buyers-and-sellers/39.html

According to their FAQ, btc's are only marked as reserved when there is an sell order open.
Is it possible you accidentally created a sell order, which hasn't been fulfilled yet? Not sure why they don't show up in your screens.
Its quite strange you don't see any sell orders. I think the only one able to help you in this case is the support of bitcoin.de

Quote from: darkangel11 on January 13, 2018, 07:09:19 PM

I have used that site before and when your coins are seen as "reserved" it means that you've sold them but haven't released the payment

In such a case it should mark the coins as blocked, not reserved.

Quote from: PassiTheApe on January 13, 2018, 09:53:46 AM

This is the transaction from when I originally deposited my BTC from my Electrum wallet to bitcoin.de, is there anything wrong with it?
https://blockchain.info/tx/5369a3eb60e397fabaf61df889cd2ff2deb8de9350eef56997f23f7678792b17

Everything is fine with the TX. It got confirmed >1 month ago.