Here you can see the return of the Ukrainian war prisoners (also some musicians) from Wetzlar on march 3d 1918 - the recordings took probably place shortly afterwards on their way home on stopover in Berlin: https://www.filmportal.de/node/1196306/video/1197760
My best estimate for the recording date, from the matrix numbers alone, has been April 1918. In view of Raoul Konezni’s exactly dated video link I’ll happily amend that to March 1918 now. Thank you! One more little puzzle-piece recovered.
PS: Also happy to see you alive and well, Raoul. Not something one can take for granted in these crazy times.....