BUG Purchase order Discount stays 0

DOLIBARR ENVIRONMENT
- Version: 8.0.3
- Operating System: 2.6.32-754.6.3.el6.x86_64 #1 SMP Tue Oct 9 17:27:49 UTC 2018 x86_64
- Web Server: Apache
- PHP: 5.6.38
- Database: MySQL
- URL(s): htdocs/fourn/commande/

When buying a an item with a supliersprice and discount the discount stays 0.