Scienceblogs.de, a German science blogging portal, includes a relatively famous list of 50 unsolved ciphers, which range from cryptograms published by serial killers to the famous Voynich manuscript.
Among these ciphers is a set of German radio messages from World War I that were encoded using the ADFGVX method.
GPT-6 Astra solved this cipher, and believes that the original message was as follows.
https://www.prinzai.com/p/gpt-6-astra-solves-a-wwi-german-radio