Exporting concert pitch score to MusicXML results in parts being transposed, but not key signatures.
- Create a score with a transposing instrument (e.g. clarinet).
- Set the score to concert pitch.
- Enter some notes
- Export the score as MusicXML.
- Open the exported MusicXML file.
The notes in the opened file will have the notes of the transposed score, but the key signature of the concert pitch score.
More specifically, the exported XML retains the transpose element and transposes the notes accordingly, as if it were a transposed score. As discussed in https://musescore.org/en/node/15373, this behaviour is probably correct. However, the key signatures are not transposed, and are exported as if they are in concert pitch.
Workaround: export with concert pitch turned off