The section 4.1 The anchor-size() Function hasn't been framed like the 3.2. New Sizing Values: the stretch, fit-content, and contain keywords section.
So the w3c/webref crawler can't relate the value to the properties that can take it. The section needs to be formatted as explained below:
As done in css-sizing-4, css-anchor-position would ideally list the impacted CSS properties in a table with a "New Values" row instead of only saying so in prose.
Also, the section needs to mention that the value also applies to logical sizing properties. It also needs to mention properties agreed in the latest resolution.