In record picker LWC component on desktop, when the search text doesn't match any of the records, an error message is displayed out-of-the-box "Select an option or remove the entered text". However, the same does not happen in Field Service Mobile app.
This behavior that is seen is the current behavior of the recordPicker on mobile. In Field Service Mobile app, the component acts as a faux input that opens a modal when a user begins typing a search term. If no record is selected within the modal, the only way to return is by closing the modal, which resets the component to its initial state with an empty faux input. As a result, no error message is displayed in this scenario.
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