Translation and language relations
Compare language plugin and SEO plugin: hreflang target and canonical must mean the same language version that is actually desired.
With WordPress, language URLs are often linked by an extension. Check whether the affected contributions belong together as translations and whether both have been published. Even inserted hreflang tags may differ from this assignment.
Where to check the setting in WordPress
In the translation tool used, open the assignment of the affected contribution. Compare published translations with the hreflang URLs in the head; a manually inserted language link in the menu does not automatically generate this assignment.
Example of this specific finding
Illustrative control case: An English performance page is called as a language alternative, but its canonical points to the German version. Translation and duplicate consolidation are contradictory.
follow-up audit in WordPress
Test each published translation with their canonical and counter references. The mere existence of a language flag does not confirm a correct language set.
Maintain independent language versions with their respective matching canonical URL. Test language set and canonical goals together.
Derogations and scope
Almost identical regional sides of the same language may require a differentiated decision; different languages may not be combined in a blanket manner.
Related: WordPress with classic or block theme. SEO plugins and page builders are different; there is no universal menu path for all installations.
Classify the general error
Definition, system-independent causes and further correction examples: Keeping translations and real duplicates apart