Comment # 7 on bug 1095749 from Ladislav Slez�k

Sergio, does the problem happen when you save the changes and exit YaST, start
it again and then try changing the priority of the new repo?

YaST caches the data for the new repositories, the changes are saved at exit.
Maybe it is related.

Please also check if there is any file under /etc/zypp/services.d/.