Are you sure?
By the way: I observed zypper dist-upgrade switching packages between repos. However eventually zypper got permission to decide everything on its own on all hosts maintained by me:
3400g:~ # grep Allow /etc/zypp/zypp.conf
# solver.dupAllowDowngrade = true
# solver.dupAllowNameChange = true
# solver.dupAllowArchChange = true
solver.dupAllowVendorChange = true
3400g:~ #
All hosts now use the above settings. zypper dist-upgrade runs unattended in the background. Selection of package versions is governed by repo priorities.
The above strategy is closely monitored on a dozen machines, half of them operated by Linux illiterate users. Their comments may be summarized as: “I don’t know what Linux does, but it always works”.
Host 3400g does a daily dup. Decisions made by zypper since May 12 are few and benign:
3400g:~ # journalctl -q -u dup -g change
Jun 16 13:56:33 3400g zypper[9257]: The following package is going to change architecture:
Jun 16 13:56:33 3400g zypper[9257]: 1358 packages to upgrade, 58 new, 12 to remove, 1 to change arch.
Jun 16 14:22:33 3400g zypper[9257]: usermod: no changes
3400g:~ #