The "no results found" slot of the Lookup component is an li tag inside a ul. The ul is marked with the aria role listbox, but the li lacks any role. This is (according to cypress-axe) not aria-conformant.
Add the option role to the li, so that the listbox has an option child, and that the li has a semantic role.
Example cypress-axe output:
┌─────────┬──────────────────────────┬────────────┬───────────────────────────────────────────────────────────────────────────┬───────┐ │ (index) │ id │ impact │ description │ nodes │ ├─────────┼──────────────────────────┼────────────┼───────────────────────────────────────────────────────────────────────────┼───────┤ │ 0 │ 'aria-required-children' │ 'critical' │ 'Ensure elements with an ARIA role that require child roles contain them' │ 1 │ │ 1 │ 'listitem' │ 'serious' │ 'Ensure <li> elements are used semantically' │ 1 │ └─────────┴──────────────────────────┴────────────┴───────────────────────────────────────────────────────────────────────────┴───────┘
