Shares of European aerospace giant Airbus fell as much as 10% on Monday, following reports the company has discovered an industrial quality issue regarding dozens of A320-family aircraft.

The flaw, which is said to affect the aircraft’s fuselage panels, is delaying some deliveries but there are no immediate indications that it has reached aircraft in service, Reuters reported, citing unnamed sources.

Airbus was not immediately available to comment when contacted by CNBC.

Paris-listed shares of Airbus plunged to the bottom of the pan-European Stoxx 600 index on the news. The stock traded 9.3% lower at 12:26 p.m. London time (7:26 a.m. ET), on track for its biggest daily drop since June last year, according to LSEG data.

The latest report comes after Airbus said the vast majority of the roughly 6,000 A320-family aircraft impacted by a software glitch over the weekend had now received the necessary modifications.

In a statement published Monday, Airbus apologized for delays caused to passengers and airlines impacted by the software issue, which affected more than half of the narrow-body fleet and forced airlines to ground jets during one of the busiest travel weekends of the year.

The directive — among the largest in the 55-year history of Airbus — quickly spilled into U.S. holiday travel and stretched to Australia. The disruption, linked to solar flares, hit especially hard in Asia, where the single-aisle A320 family anchors short-haul networks.

Shares of French aerospace and defense firm Thales, which supplied the flight system software to Airbus, were last seen trading 3.1% lower.

— CNBC’s Victor Loh contributed to this report.