0 bytes, that is failing chunked uploads on nginx/php-fpm setups (which is what murena runs too). Apache apparently got a fix:
- WebDAV upload produces empty files for one provider · bitfireAT/davx5-ose · Discussion #326 · GitHub
- Chunked transfers lead to 0 byte files · Issue #7995 · nextcloud/server · GitHub
- Nextcloud backups only write 0 byte files to server · Issue #907 · seedvault-app/seedvault · GitHub
will look into docs