There are no exceptions for not providing this notice. Whether you provide it after the fact will be a management decision. IMHO it should be provided.
The requirement is triggered by the use (not the pull), so yes it should have been sent.
The NHLA is required to be provided only once for each loan request but it does have to be provided for each loan request.
(g) Disclosure of Credit Scores by Certain Mortgage Lenders
(1) In general. Any person who makes or arranges loans and who uses a consumer credit score, as defined in subsection (f), in connection with an application initiated or sought by a consumer for a closed end loan or the establishment of an open end loan for a consumer purpose that is secured by 1 to 4 units of residential real property (hereafter in this subsection referred to as the “lender”) shall provide the following to the consumer as soon as reasonably practicable:
If you use a previously acquired credit score from a another loan request then you still have to provide the notice for the new loan request. The purpose of the notice is to inform the applicant the credit score used and the date the credit score was generated.
The opinions expressed are mine and they are not to be taken as legal advice.