CI failes with the following error message:
```
Merge Failed.
This change or one of its cross-repo dependencies was unable to be automatically merged with the current state of its repository. Please rebase the change and upload a new patchset
```
even on changes that include no cross-repo dependencies and are up-to-date with the current master branch of their repo. See for example this Wikibase change: [DNM CI test (I6bd9ed37)](https://gerrit.wikimedia.org/r/c/mediawiki/extensions/Wikibase/+/949015)
**Things that were tried so far**
* Fetching puppet on zuul https://sal.toolforge.org/log/7szV-IkBhuQtenzvIe8C
* Restarting zuul: https://sal.toolforge.org/log/D83v-IkBhuQtenzvGyJz
* helped for a very short time, errors quickly started up again
**Prior similar incidents**
* In May 2022, there was T309371 and T308943 for which {T309376} was identified as the root cause.
**Prior documentation**
* https://www.mediawiki.org/wiki/Continuous_integration/Zuul#All_Gerrit_patches_complain_of_merge_conflicts (has only a very little bit, pointing to the above tasks)