Warning 'useAsyncData must return a value (it should not be undefined) (...)' triggered for server route returning null or '' #28920
Description
Environment
n/a
Reproduction
https://stackblitz.com/edit/github-9s3uba
Describe the bug
Warning 'useAsyncData must return a value (it should not be undefined) or the request may be duplicated on the client side.' occurs when calling server route which returns null or ''.
Additional context
Mentioned in #28096 (comment)
Logs
No response