Sorry for replying in English. BSV is a fork of BCH, so some services will still show you the BCH address format for BSV transactions. To maintain compatibility, Coinomi allows sending to a BCH address format, but will automatically display the legacy BTC format when sending. This is explained on the article here: https://coinomi.freshdesk.com/support/solutions/articles/29000018980-new-bch-address-format
This is most likely what explains the visual change in address. It doesn't alter the actual destination, if you sent to the BSV deposit address for bitcoin.de, your coins will still be sent correctly.
Please open a support ticket at support.coinomi.com explaining the issue in detail so we can take a better look