Input Tax Credit discrepancy procedure: verify documentary ITC conditions and require professional or supplier certification before adjustment. Clarification prescribes that where ITC claimed in FORM GSTR-3B does not appear in FORM GSTR-2A for FY 2017-18 and 2018-19, proper officers must obtain invoice details and verify statutory ITC conditions-possession of tax invoice or documents, receipt of goods or services, payment to the supplier, applicability of reversals and timeliness of claim-and require certification from Chartered/Cost Accountants with UDIN or supplier certificates as specified; guidance is limited to bona fide reporting errors and applies only to ongoing proceedings and pending adjudications or appeals.