I have the same problem after updating from 1.0.20 to 1.0.30 and inserting any player/instrument in the German version. But I think, no instrument is missing - scroll down in the lists or search for instrument and you’ll find the instruments.
The difference between English and German version is, that there are no empty entries at the beginning of the English instruments lists.
In my opinion it is a problem of incorrect indexing or linking of entries in the instrument table in the german version.
Following instrument groups are affected in the german version:
@Dorico-Team: could you please check this?