Well, the security report itself talks about suspected cases (Verdachtsfallmeldungen in German), so I guess it's fair to call them that:

> In 1.919 Verdachtsfallmeldungen wurde über einen tödlichen Ausgang in unterschiedlichem zeitlichem Abstand zur Impfung (0 Tage bis 289 Tage) berichtet.

Also note that not every death after vaccination is reported, you need to fill a document with your symptoms [1]. So these are indeed very much suspected cases of adverse side effects / deaths.

[1]: https://nebenwirkungen.bund.de/nw/DE/home/home_node.html