Comment # 42 on bug 1172073 from Dominique Leuenberger

https://openqa.opensuse.org/tests/1642962#step/zdup/17

We seem to have missed kernel-default-base here

File /boot/.vmlinuz-5.10.16-1-default.hmac
  from install of
     kernel-default-base-5.10.16-1.3.18.2.x86_64 (repo1)
  conflicts with file from package
     kernel-default-base-5.10.16-1.2.18.1.x86_64 (@System)

(a rebuild, resulting in the originally mentioned conflict)