Last month, a report by IHS’ iSuppli claimed the iPad 2 shortages Apple had to face in the quarter (with 4.69 million units sold announced at the Q2 2011 earnings call, well below Wall Street’s analysts’ estimates) were caused by production issues with the IPS display and built-in speaker of the device. Whilst the report didn’t provide additional details on the reasons behind the display manufacturing issues, iSupply wrote “quality concerns” affected Apple’s estimated number of initial iPad 2 shipments. The company mentioned “lamination issues with one of the touch suppliers”, yet stating that Apple was on track to increase the volume of iPad shipments in the next quarter, as also mentioned by Tim Cook when referring to the iPad 2 as the “mother of all backlogs.”

A new report by Digitimes today claims the production issues with the iPad’s display were caused by light leakage issues in LG’s units, with LG shipping only 3.2 million display units in the quarter.

In other news, Samsung Electronics shipped a total of four million 9.7-inch panels for iPads in the first quarter, outpacing rival LG Display (LGD) as the largest tablet PC panel supplier for Apple, the sources indicated. LGD’s iPad panel shipments reached only 3.2 million units in the first quarter.

LGD was forced to reduce its shipments in the first quarter due to light leakage problem for panels produced at its 6G production lines. The company reportedly has fixed the problem and will resume shipment momentum to Apple in the second quarter, said the sources.

Digitimes does not relate LG’s manufacturing issues with overall iPad shortages in Apple’s Q2, but the report seems to corroborate iSuppli’s previous claims of shipments below estimates due to problems in the iPad production chain.