When creating a new Paper project for MC 1.17 or 1.17.1 (so versions using the new Paper artifact maven groups) - no bukkit or spigot API is actually added to a project, I guess it always was a transitive dependency but now isn't (?). For older MC versions - adding just paper-api works fine.
So I'd like to suggest adding also a spigot-api dependency when creating a new Paper project.