The current description in org.springdoc.core.converters.models.Pageable for the sort field reads in part Sorting criteria in the format: property(,asc|desc).. The comma should go outside the parens, because the current implication is that there is only a comma if the sort order is ascending.

https://sourcegraph.com/github.com/springdoc/springdoc-openapi@008aad6de05b211ab83fdd052ab3ced1d85bd2bf/-/blob/springdoc-openapi-common/src/main/java/org/springdoc/core/converters/models/Pageable.java?L55