defineProps, Invalid prop: type check failed for prop "valueExpr" Expected Object

hi, i have mi child component with:

const props = defineProps<{ valueExpr: { type: string, default: "descrizione", }, }>()

i call this child on my parent:

but console firefox show this error: Invalid prop: type check failed for prop "valueExpr". Expected Object, got String with value "cod_istat_comune".

any help ?

br Max