Dropbox upload with mute: true does not work

If I use the curl example from the dropbox api spec replacing "mute": false by "mute": true

curl -X POST https://content.dropboxapi.com/2/files/upload \
--header "Authorization: Bearer " \
--header "Dropbox-API-Arg: {\"path\": \"/Homework/math/Matrices.txt\",\"mode\": \"add\",\"autorename\": true,\"mute\": true}" \
--header "Content-Type: application/octet-stream" \
--data-binary @local_file.txt

the file is uploaded correctly but , I still receive a file update notice.

Johannes