Comment # 2 on bug 1187887 from Walter Karig

(In reply to Marcus Meissner from comment #1)
> this is not due to zypper, but due to repo setup.

What do you mean by "repo setup"?

The setup of repo-sle-update (Update repository with updates from SUSE Linux
Enterprise 15, http://download.opensuse.org/update/leap/15.3/sle/),

or

the setup of the repositories on my local machine?

Here are only the standard repositories of openSUSE Leap:

15.2 before dup:
$ zypper lr -E
[...]
#  | Alias               | Name                        | [...]
---+---------------------+-----------------------------+ [...]
 5 | repo-non-oss        | Non-OSS Repository          | [...]
 6 | repo-oss            | Main Repository             | [...]
 9 | repo-update         | Main Update Repository      | [...]
10 | repo-update-non-oss | Update Repository (Non-Oss) | [...]

Now 15.3 via dup:
$ zypper lr -E
[...]
#  | Alias                 | Name [...]
---+-----------------------+------------------------------------------- [...]
 2 | repo-backports-update | Update repository of openSUSE Backports [...]
 7 | repo-non-oss          | Non-OSS Repository [...]
 8 | repo-oss              | Main Repository [...]
10 | repo-sle-update       | Update repository with updates from SLE 15 [...]
13 | repo-update           | Main Update Repository [...]
14 | repo-update-non-oss   | Update Repository (Non-Oss) [...]