Core output, SEO plugin and theme head
If the canonical calls an earlier permalink, check the saved override and the final post address. The forwarding itself is not the input point of the canonical.
On a single content page, check if WordPress Core, SEO plugin, and theme each output canonicals. For archives, a different logic may apply than for contributions. Do not blindly remove the core function, but first determine the leading source.
Where to check the setting in WordPress
Open the head of a published single view and search for rel=canonical. Assign the output to the core call rel_canonical, the active SEO plugin or your own theme snippet. A second manual output in the header does not fix an incorrect plugin value.
Example of this specific finding
Illustrative control case: The canonical points to /ratgeber-alt/, this address redirects to /ratgeber/. The desired final URL is already known.
follow-up audit in WordPress
Compare a post, a static page and an archive. The additional tag comes from a theme snippet, the change of which is first checked in a test environment.
Spend the final matching goal directly in the canonical. Orient sitemap and internal links to the same address and verify their response.
Derogations and scope
A forwarding does not automatically make the content unusable. The result initially shows an unnecessary or possibly contradictory intermediate signal.
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: Deposit the final address in the canonical