Question about on User input workflows

Question about on User input workflows

In my app I have a field for device IMEI which should trigger a check on an external API through an invokeUrl. But it seems the workflow will only run after the user has moved the focus away from the field by clicking somewhere else. However, if the user just fills the form and click Submit without moving the focus away the workflow will not run.

Is this the expected behavior and how can I force the check if the user clicks submit without moving the focus away from the field?