Is it possible to read a Customer Metafield from a checkout UI extension only app?

In attempting to read a Customer metafield, all of the following react hooks return undefined or 0 length array {useAppMetafields(), useMetafields(), useMetafield()}.

(I can read Order metafields with the useMetafield() react hook.)

I have added the following scopes to in and pushed the config and verified I see them in partner portal = “read_customers,write_customers,customer_read_customers,customer_write_customers,read_checkouts,write_checkouts,unauthenticated_read_checkouts,unauthenticated_write_checkouts,unauthenticated_read_customers,unauthenticated_write_customers”

I have defined the customer metafield in the store and in the extension toml file just after the target definition.

I have restarted dev several times.

Is it possible to read a Customer Metafield from a checkout UI extension only app v3.48.4?

@shopify/app”: “3.48.4”,
@shopify/cli”: “3.48.4”,
“react”: “^17.0.2”