I think the print was apparently in very good condition, but as so often happens with prints from this "pasted" post laminated era, the sound was present on one track or another for periods. Never, during these problem areas, on both tracks simultaneously.
The fact it was in German, doesn't necessarily mean it was re recorded.
Many prints from Derann were offered in English or German languages.
Either way, for the vast majority of us here, having the language in German, is totally useless to us unless there is a high probability it would be able to be dubbed in English.
On this particular print, given my previous experience at trying to correct these type of prints, I would say there is a very high probability that this would be unlikely with any modicum of complete success.