SEO Checkup is reporting I have an Anchor IDs issue.
Relative links (internal) that use anchor tags to send users to specific content snippets require IDs on those receiving pages. This check exists to make sure the links on the crawled page actually have corresponding IDs on the page they link to.
One or more relative anchors on this page don’t have corresponding IDs on their destination pages.
If you are going to use relative anchor tags, they best go somewhere or they are misleading to your visitors.
How to Fix
Locate the affected anchor tags on the page and edit the URLs and remove the hash. Alternately, add the required IDs to those destination pages.
This does not include an example of the problem which in my opinion is necessary if the site has many internal links on a page. It would be nice if this feature actually shared what it found instead of just teasing a problem to the user.